kalakadu.com: Aldehydes, Ketones And Carboxylic Acids Class 12th Chemistry Part Ii CBSE Solution

Aldehydes, Ketones And Carboxylic Acids Class 12th Chemistry Part Ii CBSE Solution

Class 12^th Chemistry Part Ii CBSE Solution

Intext Questions Pg-353
α-Methoxypropionaldehyde Write the structures of the following compounds.…
3-Hydroxybutanal Write the structures of the following compounds.…
2-Hydroxycyclopentane carbaldehyde Write the structures of the following compounds.…
4-Oxopentanal Write the structures of the following compounds.
Di-sec. butyl ketone Write the structures of the following compounds.…
4-Fluoroacetophenone Write the structures of the following compounds.…
Intext Questions Pg-356
Write the structures of products of the following reactions;(i) (ii) (iii) (iv)…
Intext Questions Pg-358
Arrange the following compounds in increasing order of their boiling points.CH3CHO,…
Intext Questions Pg-365
Ethanal, Propanal, Propanone, Butanone. Hint: Consider steric effect and electronic…
Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone. Hint: Consider steric…
Predict the products of the following reactions: (i) (ii) (iii) (iv)…
Intext Questions Pg-367
Ph CH2CH2COOH Give the IUPAC names of the following compounds:
(CH3)2C = CHCOOH Give the IUPAC names of the following compounds:…
Give the IUPAC names of the following compounds:
Give the IUPAC names of the following compounds:
Intext Questions Pg-370
Ethylbenzene Show how each of the following compounds can be converted to benzoic acid.…
Acetophenone Show how each of the following compounds can be converted to benzoic acid.…
Bromobenzene Show how each of the following compounds can be converted to benzoic acid.…
Phenylethene (Styrene) Show how each of the following compounds can be converted to…
Intext Questions Pg-376
CH3CO2H or CH2FCO2H Which acid of each pair shown here would you expect to be stronger?…
CH2FCO2H or CH2ClCO2H Which acid of each pair shown here would you expect to be stronger?…
CH2FCH2CH2CO2H or CH3CHFCH2CO2H Which acid of each pair shown here would you expect to be…
Which acid of each pair shown here would you expect to be stronger?…
Exercises
Cyanohydrins What is meant by the following terms? Give an example of the reaction in each…
Acetal What is meant by the following terms? Give an example of the reaction in each case.…
Semicarbazone What is meant by the following terms? Give an example of the reaction in…
Aldol What is meant by the following terms? Give an example of the reaction in each case.…
Hemiacetal What is meant by the following terms? Give an example of the reaction in each…
Oxime What is meant by the following terms? Give an example of the reaction in each case.…
Ketal What is meant by the following terms? Give an example of the reaction in each case.…
Imine What is meant by the following terms? Give an example of the reaction in each case.…
2,4-DNP-derivative What is meant by the following terms? Give an example of the reaction…
Schiff’s base What is meant by the following terms? Give an example of the reaction in…
CH3CH(CH3)CH2CH2CHO Name the following compounds according to IUPAC system of…
CH3CH2COCH(C2H5)CH2CH2Cl Name the following compounds according to IUPAC system of…
CH3CH=CHCHO Name the following compounds according to IUPAC system of nomenclature:…
CH3COCH2COCH3 Name the following compounds according to IUPAC system of nomenclature:…
CH3CH(CH3)CH2C(CH3)2COCH3 Name the following compounds according to IUPAC system of…
(CH3)3CCH2COOH Name the following compounds according to IUPAC system of nomenclature:…
OHCC6H4CHO-p Name the following compounds according to IUPAC system of nomenclature:…
3-Methylbutanal Draw the structures of the following compounds.
p-Nitropropiophenone Draw the structures of the following compounds.…
p-Methylbenzaldehyde Draw the structures of the following compounds.…
4-Methylpent-3-en-2-one Draw the structures of the following compounds.…
4-Chloropentan-2-one Draw the structures of the following compounds.…
3-Bromo-4-phenylpentanoic acid Draw the structures of the following compounds.…
p,p’-Dihydroxybenzophenone Draw the structures of the following compounds.…
Hex-2-en-4-ynoic acid Draw the structures of the following compounds.…
CH3CO(CH2)4CH3 Write the IUPAC names of the following ketones and aldehydes. Wherever…
CH3CH2CHBrCH2CH(CH3)CHO Write the IUPAC names of the following ketones and aldehydes.…
CH3(CH2)5CHO Write the IUPAC names of the following ketones and aldehydes. Wherever…
Ph-CH=CH-CHO Write the IUPAC names of the following ketones and aldehydes. Wherever…
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give…
PhCOPh Write the IUPAC names of the following ketones and aldehydes. Wherever possible,…
The 2, 4-dinitrophenylhydrazone of benzaldehyde Draw structures of the following…
Cyclopropanone oxime Draw structures of the following derivatives.…
Acetaldehydedimethylacetal Draw structures of the following derivatives.…
The semicarbazone of cyclobutanone Draw structures of the following derivatives.…
The ethylene ketal of hexan-3-one Draw structures of the following derivatives.…
The methyl hemiacetal of formaldehyde Draw structures of the following derivatives.…
PhMgBr and then H3O+ Predict the products formed when cyclohexanecarbaldehyde reacts with…
Tollens’ reagent Predict the products formed when cyclohexanecarbaldehyde reacts with…
Semicarbazide and weak acid Predict the products formed when cyclohexanecarbaldehyde…
Excess ethanol and acid Predict the products formed when cyclohexanecarbaldehyde reacts…
Zinc amalgam and dilute hydrochloric acid Predict the products formed when…
Which of the following compounds would undergo aldol condensation, which the Cannizzaro…
Butane-1,3-diol How will you convert ethanal into the following compounds?…
But-2-enal How will you convert ethanal into the following compounds?…
But-2-enoic acid How will you convert ethanal into the following compounds?…
Write structural formulas and names of four possible aldol condensation products from…
An organic compound with the molecular formula C9H10O forms 2,4-DNP derivative, reduces…
An organic compound (A) (molecular formula C8H16O2) was hydrolysed with dilute sulphuric…
Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert-butyl ketone (reactivity towards…
CH3CH2CH(Br)COOH, CH3CH(Br)CH2COOH, (CH3)2CHCOOH, CH3CH2CH2COOH (acid strength) Arrange…
Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid…
Propanal and Propanone Give simple chemical tests to distinguish between the following…
Acetophenone and Benzophenone Give simple chemical tests to distinguish between the…
Phenol and Benzoic acid Give simple chemical tests to distinguish between the following…
Benzoic acid and Ethyl benzoate Give simple chemical tests to distinguish between the…
Pentan-2-one and Pentan-3-one Give simple chemical tests to distinguish between the…
Benzaldehyde and Acetophenone Give simple chemical tests to distinguish between the…
Ethanal and Propanal Give simple chemical tests to distinguish between the following pairs…
Methyl benzoate How will you prepare the following compounds from benzene? You may use any…
m-Nitrobenzoic acid How will you prepare the following compounds from benzene? You may use…
p-Nitrobenzoic acid How will you prepare the following compounds from benzene? You may use…
Phenylacetic acid How will you prepare the following compounds from benzene? You may use…
p-Nitrobenzaldehyde. How will you prepare the following compounds from benzene? You may…
Propanone to Propene How will you bring about the following conversions in not more than…
Benzoic acid to Benzaldehyde How will you bring about the following conversions in not…
Ethanol to 3-Hydroxybutanal How will you bring about the following conversions in not more…
Benzene to m-Nitroacetophenone How will you bring about the following conversions in not…
Benzaldehyde to Benzophenone How will you bring about the following conversions in not…
Bromobenzene to 1-Phenylethanol How will you bring about the following conversions in not…
Benzaldehyde to 3-Phenylpropan-1-ol How will you bring about the following conversions in…
Benazaldehyde to α-Hydroxyphenylacetic acid How will you bring about the following…
Benzoic acid to m- Nitrobenzyl alcohol How will you bring about the following conversions…
Acetylation- Describe the following:
Cannizzaro reaction Describe the following:
Cross aldol condensation Describe the following:
Decarboxylation Describe the following:
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
CH3COCH2COOC2H5 Complete each synthesis by giving missing starting material, reagent or…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Complete each synthesis by giving missing starting material, reagent or products…
Cyclohexanone forms cyanohydrin in good yield but 2,2,6-trimethylcyclohexanone does not.…
There are two -NH2 groups in semicarbazide. However, only one is involved in the formation…
During the preparation of esters from a carboxylic acid and an alcohol in the presence of…
An organic compound contains 69.77% carbon, 11.63% hydrogen and rest oxygen. The molecular…
Although phenoxide ion has more number of resonating structures than carboxylate ion, the…

Intext Questions Pg-353

Question 1.
Write the structures of the following compounds.

α-Methoxypropionaldehyde

Answer:
The compound contains ether group and an aldehydic functional group with the longest chain having 3 carbon atoms. α

means the position of the carbon atom attached to attached to the carbon atom of the functional group, in this case, it is an aldehyde functional group.

Question 2.
Write the structures of the following compounds.

3-Hydroxybutanal

Answer:
The compound contains an alcoholic group and an aldehydic functional group with the longest chain having 4 carbon atoms. The numbering of the chain starts from a carbon atom of aldehyde group.

Question 3.
Write the structures of the following compounds.

2-Hydroxycyclopentane carbaldehyde

Answer:
The compound contains alcoholic group and an aldehydic functional group with the longest chain having 5 carbon atoms which are cyclic in nature. The numbering of the chain starts from a carbon atom of aldehyde group attached to the cyclopentane ring.

Question 4.
Write the structures of the following compounds.

4-Oxopentanal

Answer:
The compound contains ketone group and an aldehydic functional group with the longest chain having 5 carbon atoms. The numbering of the chain starts from a carbon atom of aldehyde group.

Question 5.
Write the structures of the following compounds.

Di-sec. butyl ketone

Answer:
The compound contains ketone functional group with the longest chain having 8(butyl is used because there is two similar butyl group attached to the carbonyl carbon of ketone group) carbon atoms.

Question 6.
Write the structures of the following compounds.

4-Fluoroacetophenone

Answer:
The compound contains a fluorine atom and a ketone functional group with the longest chain which is a derivative of a phenyl group and an acetyl substituent.

Intext Questions Pg-356

Question 1.
Write the structures of products of the following reactions;

(i)

(ii)

(iii)

(iv)

Answer:
(i)

(ii)

(iii)

(iv)

Intext Questions Pg-358

Question 1.
Arrange the following compounds in increasing order of their boiling points.

CH₃CHO, CH₃CH₂OH, CH₃OCH₃, CH₃CH₂CH₃

Answer:
The molecular masses of the given compounds are in the range of 44-66 g/mol. The second molecule, CH₃CH₂OH contains OH alcoholic group due to which it undergoes extensive H bonding with each other, leading to the association of the molecules. Therefore it has a highest boiling point. In the molecule CH₃CHO , there is strong intermolecular dipole-dipole attraction due to presence of -CHO aldehydic group( as H will have partial positive charge and oxygen will have partial negative charge , so there will attraction between molecules),which is weak in case of CH₃OCH₃ as both CH₃ groups have +I effect which results in decrease in electron affinity for the oxygen attached to it( with no partially positive H atom). And in CH₃CH₂CH₃ there are only weak van der Waals forces of attraction. So the compounds in increasing order of their boiling point are:
CH₃CH₂CH₃<CH₃OCH₃<CH₃CHO<CH₃CH₂OH.

Intext Questions Pg-365

Question 1.
Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.

Ethanal, Propanal, Propanone, Butanone.

Hint: Consider steric effect and electronic effect.

Answer:
The +I effect increases in the order as:

Ethanal<Propanal<Propanone<Butanone.

Therefore the electron density of the carbonyl carbon increases as the +I effect due to the alkyl group increases. As a result, the chances of attack by a nucleophile (which are rich in electron and carries a negative charge, not necessary usually have a lone pair of an electron) decreases because the carbonyl carbon has electron density on it. Hence the increasing order of the reactivities of given compounds in nucleophilic addition reaction is:

Ethanal > Propanal> Propanone > Butanone.

Question 2.
Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.

Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone.

Hint: Consider steric effect and electronic effect.

Answer:

The +I effect is more in ketone than in aldehyde because in ketone there are 2 alkyl groups contributing in the +I effect whereas in aldehydes there is only one alkyl group. Hence, acetophenone(being ketone group attached to it) is the least reactive in nucleophilic addition reactions. Among aldehydes, the +I effect is the highest in p-tolualdehyde because of the presence of the electron-donating –CH₃ group(which increase the electron density on the carbonyl carbon via resonance through the benzene ring) and the lowest in p-nitrobenzaldehyde because of the presence of the electron-withdrawing –NO₂ group(which decreases the electron density on the carbonyl carbon via resonance through the benzene ring). Hence, the increasing order of the reactivities of the given compounds is:

Acetophenone<p-tolualdehyde<Benzaldehyde<p-Nitrobenzaldehyde

Question 3.
Predict the products of the following reactions:

(i)

(ii)

(iii)

(iv)

Answer:
(i)

Cyclopentanone reacts with hydroxylamine to give cyclopentanone oxime. As you can see the cyclopentanone has ketone functional group with oxygen attached to carbonyl carbon and the hydroxylamine has two H atoms attached to N. And hence in the product this O and two H atoms are removed and form a water molecule.

(ii)

(iii)

(iv)

Trick: remember if any aldehyde or ketone bearing compound reacts with primary or secondary amine then for finding the product formed simply remove the oxygen atom from the aldehyde or ketone functional group and two H atoms attached to N in amines and add a double bond between C and N.

Intext Questions Pg-367

Question 1.
Give the IUPAC names of the following compounds:

Ph CH₂CH₂COOH

Answer:
The compound contains carboxylic acid as the functional group and Ph means a phenyl group. The longest chain contains 3 carbon atom with phenyl group of carbon 3 so the IUPAC name of the compound is 3-phenylpropanoic acid.

Question 2.
Give the IUPAC names of the following compounds:

(CH₃)₂C = CHCOOH

Answer:
The longest chain contains 4 carbon atom with a methyl group as a substituent and a carboxylic acid as a functional group. The no. Of the chain starts from the carbon atom of the –COOH group with double bond on carbon 2 so the IUPAC name of the compound is 3-Methylbut-2-enoic acid.

Question 3.
Give the IUPAC names of the following compounds:

Answer:
The longest chain has 5 carbon atom(all are saturated) which are cyclic with the carboxylic group attached and a methyl group as a substituent. The no. Of the chain starts from the carbon atom of the –COOH group so the IUPAC name of the compound is 2-Methylcyclopentane carboxylic acid.

Question 4.
Give the IUPAC names of the following compounds:

Answer:
The longest chain is derivative of benzene with the carboxylic group attached and 3 nitro groups. The no. Of the chain starts from the carbon atom of the –COOH group so the IUPAC name of the compound is 2,4,6-Trinitrobenzoic acid.

Intext Questions Pg-370

Question 1.
Show how each of the following compounds can be converted to benzoic acid.

Ethylbenzene

Answer:

In the presence of nascent oxygen i.e. [O] along with KMnO₄/ KOH(it is a very strong oxidizing agent which oxidizes the whole alkyl group to carboxylic salt) followed by hydrolysis leads to the formation of benzoic acid. Carbon dioxide and water are formed as byproducts.

Question 2.
Show how each of the following compounds can be converted to benzoic acid.

Acetophenone

Answer:
The oxidation with alcoholic KMNO₄ followed by hydrolysis leads to the formation of benzoic acid. The reaction is given below:

Question 3.
Show how each of the following compounds can be converted to benzoic acid.

Bromobenzene

Answer:
Bromobenzene is first reacted with magnesium in presence of dry ether to give an intermediate which on reaction with solid carbon dioxide followed by hydrolysis leads to the formation of benzoic acid.

Question 4.
Show how each of the following compounds can be converted to benzoic acid.

Phenylethene (Styrene)

Answer:
Here the oxidation of styrene with alcoholic KMNO₄ is followed by hydrolysis leads to the formation of benzoic acid.

Intext Questions Pg-376

Question 1.
Which acid of each pair shown here would you expect to be stronger?

CH₃CO₂H or CH₂FCO₂H

Answer:
The +I effect of –CH₃ group increases the electron density on the O-H bond. Therefore, the release of proton becomes difficult. On the other hand, the -I effect of F decreases the electron density on the O-H bond. Therefore, the proton can be released easily. Hence, CH₂FCO₂H is a stronger acid than CH₃CO₂H.

NOTE:A strong acid is an acid which dissociates completely releasing almost all of its protons in the solution.

Question 2.
Which acid of each pair shown here would you expect to be stronger?

CH₂FCO₂H or CH₂ClCO₂H

Answer:
F has stronger -I effect than Cl(as fluorine is more electronegative than chlorine). Therefore, CH₂FCO₂H can release proton more easily than CH₂ClCO₂H. Hence, CH₂FCO₂H is a stronger acid than CH₂ClCO₂H.

Question 3.
Which acid of each pair shown here would you expect to be stronger?

CH₂FCH₂CH₂CO₂H or CH₃CHFCH₂CO₂H

Answer:
Inductive effect decreases with increase in distance(the more will be the distance of the inductive group from the carboxylic group less will be its effect of polarisability). Hence, the -I effect of F in CH₃CHFCH₂CO₂H is more than it is in CH₂FCH₂CH₂CO₂H . Hence, CH₃CHFCH₂CO₂H is a stronger acid than CH₂FCH₂CH₂CO₂H .

Question 4.
Which acid of each pair shown here would you expect to be stronger?

Answer:
Due to the -I effect of F(being electronegative), it is easier to release proton in the case of compound (A). However, in the case of compound (B), the release of the proton is difficult due to the +I effect of –CH₃ i.e. methyl group. Hence, (A) is a stronger acid than (B).

Exercises

Question 1.
What is meant by the following terms? Give an example of the reaction in each case.

Cyanohydrins

Answer:
Cyanohydrin:

Cyanohydrins are those organic compounds having the formula RR“²C(OH)CN, wherever R and R“² can be alkyl or aryl groups.

Aldehydes and ketones react with compound (KCN) within the presence of excess cyanide (NaCN) as a catalyst to field organic compound.

Question 2.
What is meant by the following terms? Give an example of the reaction in each case.

Acetal

Answer:
Acetal:

Acetals are gem - dialkoxy alkanes within which 2 alkoxy teams groups attached to the terminal atom. One bond is connected to associate degree alkyl whereas the opposite is connected to the hydrogen atom.

When aldehydes are treated with 2 equivalents of a monohydric alcohol within the presence of dry HCl gas, hemiacetals are produced which are further reacted with one more molecule to alcohol to yield acetal as shown below:

Question 3.
What is meant by the following terms? Give an example of the reaction in each case.

Semicarbazone

Answer:
Semicarbarbazone:

Semicarbazones are the derivatives of organic compounds produced by the condensation reaction between a ketone or aldehyde and semicarbazide.

Semicarbazones square measure helpful for identification and characterization of aldehydes and ketones.

Question 4.
What is meant by the following terms? Give an example of the reaction in each case.

Aldol

Answer:
Aldol:

An aldol is a β-hydroxy organic compound. It's produced by the by the condensation reaction of 2 molecules of an equivalent or one molecule every of 2 totally different aldehydes or ketones within the presence of a base.

The reaction is shown as below:

Question 5.
What is meant by the following terms? Give an example of the reaction in each case.

Hemiacetal

Answer:
Hemiacetal:

Hemiacetals are α-alkoxyalcohols.

Aldehyde reacts with one molecule of a monohydric alcohol in the presence of dry HCl gas to from aloxy alcohol, known as hemiacetal.

The following reaction shows the formation of hemiacetal:

Question 6.
What is meant by the following terms? Give an example of the reaction in each case.

Oxime

Answer:
Oxime:

Oximes are a category of organic compounds having the final formula RR“²CNOH, where R is an associate organic aspect chain associated R“² is either H or an organic aspect chain. If R“² is H, then it's called aldoxime associated if R“² is an organic aspect chain, it's called ketoxime.

On treatment with hydroxylamine in a very decrepit acidic medium, aldehydes or ketones kind oximes.

Question 7.
What is meant by the following terms? Give an example of the reaction in each case.

Ketal

Answer:
Ketal:

Ketals area gem – dialkoxyalkanes in which two which 2 alkoxy teams are attached inside the chain. The opposite 2 bonds of the atom are unit connected to 2 alkyl groups.

The general structure of ketal is shown as below:

Ketones react with glycol within the presence of dry HCl gas to grant a cyclic product referred to as glycol ketals.

Question 8.
What is meant by the following terms? Give an example of the reaction in each case.

Imine

Answer:
Imine:

An organic compound which contains a carbon–nitrogen double bond.

The structure of imine is shown as below:

Imines are produced when aldehydes and ketones react with ammonia Gas.

Question 9.
What is meant by the following terms? Give an example of the reaction in each case.

2,4-DNP-derivative

Answer:
2, 4 - DNP - derivative:

2, 4 - DNP - derivative is a substituted hydrazine,

The molecular formula for 2,4-DNP–derivative is C₆H₃(NO₂)₂NHNH₂.

The other name is Dinitrophenylhydrazine is the chemical compound. Dinitrophenylhydrazine is a red to orange solid. It is a

aldehydes or ketones react with 2, 4 - dinitrophenylhydrazine to form yellow, orange, or red coloured derivatives named as 2,4 dinitrogenphenylhydrazones. These are also known as 2,4-DNP derivative.

Question 10.
What is meant by the following terms? Give an example of the reaction in each case.

Schiff’s base

Answer:
Schiff's base:

Aldehydes and ketones on react with primary amines in the presence of trace of an acid yields a Schiff's base.

Question 11.
Name the following compounds according to IUPAC system of nomenclature:

CH₃CH(CH₃)CH₂CH₂CHO

Answer:

4-methylpentanal

Question 12.
Name the following compounds according to IUPAC system of nomenclature:

CH₃CH₂COCH(C₂H₅)CH₂CH₂Cl

Answer:

Question 13.
Name the following compounds according to IUPAC system of nomenclature:

CH₃CH=CHCHO

Answer:

But-2-en-1-al

Question 14.
Name the following compounds according to IUPAC system of nomenclature:

CH₃COCH₂COCH₃

Answer:

Pentane-2,4-dione

Question 15.
Name the following compounds according to IUPAC system of nomenclature:

CH₃CH(CH₃)CH₂C(CH₃)₂COCH₃

Answer:

3,3,5-Trimethylhexan-2-one

Question 16.
Name the following compounds according to IUPAC system of nomenclature:

(CH₃)₃CCH₂COOH

Answer:

3,3-Dimethylbutanoic acid

Question 17.
Name the following compounds according to IUPAC system of nomenclature:

OHCC₆H₄CHO-p

Answer:

Benzene-1,4-dicarbaldehyde

Question 18.
Draw the structures of the following compounds.

3-Methylbutanal

Answer:
3-Methylbutanal-

Question 19.
Draw the structures of the following compounds.

p-Nitropropiophenone

Answer:
p-Nitropropiophenone-

Question 20.
Draw the structures of the following compounds.

p-Methylbenzaldehyde

Answer:
p-Methylbenzaldehyde-

Question 21.
Draw the structures of the following compounds.

4-Methylpent-3-en-2-one

Answer:
4-Methylpent-3-en-2-one-

Question 22.
Draw the structures of the following compounds.

4-Chloropentan-2-one

Answer:
4-Chloropentan-2-one-

Question 23.
Draw the structures of the following compounds.

3-Bromo-4-phenylpentanoic acid

Answer:
3-Bromo-4-phenylpentanoic acid-

Question 24.
Draw the structures of the following compounds.

p,p’-Dihydroxybenzophenone

Answer:
p,p’-Dihydroxybenzophenone-

Question 25.
Draw the structures of the following compounds.

Hex-2-en-4-ynoic acid

Answer:
Hex-2-en-4-ynoic acid-

Question 26.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.

CH₃CO(CH₂)₄CH₃

Answer:
CH₃CO(CH₂)₄CH₃

IUPAC name: Heptan-2-one

Common name: Methyl n-propyl ketone

Question 27.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.

CH₃CH₂CHBrCH₂CH(CH₃)CHO

Answer:
CH₃CH₂CHBrCH₂CH(CH₃)CHO

IUPAC name: 4-Bromo-2-methylhaxanal

Common name: (γ-Bromo-α-methyl-caproaldehyde)

Question 28.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.

CH₃(CH₂)₅CHO

Answer:
CH₃(CH₂)₅CHO

IUPAC name: Heptanal

Question 29.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.

Ph-CH=CH-CHO

Answer:
Ph-CH=CH-CHO

IUPAC name: 3-phenylprop-2-enal

Common name: β-Pheynolacrolein

Question 30.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.

Answer:

IUPAC name: Cyclopentanecarbaldehyde

Question 31.
Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.

PhCOPh

Answer:
PhCOPh

IUPAC name: Diphenylmethanone

Common name: Benzophenone

Question 32.
Draw structures of the following derivatives.

The 2, 4-dinitrophenylhydrazone of benzaldehyde

Answer:
The 2, 4-dinitrophenylhydrazone of benzaldehyde

Question 33.
Draw structures of the following derivatives.

Cyclopropanone oxime

Answer:
Cyclopropanone oxime

Question 34.
Draw structures of the following derivatives.

Acetaldehydedimethylacetal

Answer:
Acetaldehyde dimethylacetal

Question 35.
Draw structures of the following derivatives.

The semicarbazone of cyclobutanone

Answer:
The semicarbazone of cyclobutanone

Question 36.
Draw structures of the following derivatives.

The ethylene ketal of hexan-3-one

Answer:
The ethylene ketal of hexan-3-one

Question 37.
Draw structures of the following derivatives.

The methyl hemiacetal of formaldehyde

Answer:
The methyl hemiacetal of formaldehyde

Question 38.
Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

PhMgBr and then H₃O⁺

Answer:
PhMgBr and then H₃O⁺

Question 39.
Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

Tollens’ reagent

Answer:
Tollens’ reagent

Question 40.
Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

Semicarbazide and weak acid

Answer:
Semicarbazide and weak acid

Question 41.
Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

Excess ethanol and acid

Answer:
Excess ethanol and acid

Question 42.
Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

Zinc amalgam and dilute hydrochloric acid

Answer:
Zinc amalgam and dilute hydrochloric acid

Question 43.
Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.

(i) Methanal

(ii) 2-Methylpentanal

(iii) Benzaldehyde

(iv) Benzophenone

(v) Cyclohexanone

(vi) 1-Phenylpropanone

(vii) Phenylacetaldehyde

(viii) Butan-1-ol

(ix) 2,2-Dimethylbutanal

Answer:
Aldehydes and ketones having at least one α-hydrogen undergo aldol condensation. The compounds

(ii) 2-methylpentanal

(v)cyclohexanone

(vi) 1-phenylpropanone

(vii) phenylacetaldehyde

contain one or more α-hydrogen atoms. Therefore, these undergo aldol condensation.

Aldehydes having no α-hydrogen atoms undergo Cannizzaro reactions. The compounds

(i) Methanal

(iii)Benzaldehyde

(ix) 2, 2-dimethylbutanal

do not have any α-hydrogen. Therefore, these undergo cannizzaro reactions.

Compound (iv) Benzophenone is a ketone having no α-hydrogen atom and compound (viii) Butan-1-ol is an alcohol. Hence, these compounds do not undergo either aldol condensation or cannizzaro reactions.

Structures of the expected products of aldol condensation and Cannizzaro reaction-

Aldol condensation-

(ii) 2-methylpentanal-

(v)cyclohexanone-

(vi) 1-phenylpropanone-

(vii) phenylacetaldehyde –

Cannizzaro reaction-

(i) Methanal-

(iii) Benzaldehyde –

(ix) 2, 2-dimethylbutanal –

Question 44.
How will you convert ethanal into the following compounds?

Butane-1,3-diol

Answer:
Butane-1,3-diol -

Ethanol react dilute alkali produces 3-hydroxybutanal which on Reduction gives butane-1, 3-diol on reduction.

Question 45.
How will you convert ethanal into the following compounds?

But-2-enal

Answer:
But-2-enal

ethanal react with dilute alkali, gives 3-hydroxybutanal which on heating produces but-2-enal.

Question 46.
How will you convert ethanal into the following compounds?

But-2-enoic acid

Answer:
But-2-enoic acid

But-2-enal react with Tollen's reagent produced in the above reaction produces but-2-enoic acid .

Question 47.
Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as electrophile.

Answer:
(i) Taking two molecules of propanal, one which acts as a nucleophile and the other as an electrophile.

(ii) Taking two molecules of butanal, one which acts as a nucleophile and the other as an electrophile.

(iii) Taking one molecule each of propanal and butanal in which propanal acts as a nucleophile and butanal acts as an electrophile.

(iv) Taking one molecule each of propanal and butanal in which propanal acts as an electrophile and butanal acts as a nucleophile.

Question 48.
An organic compound with the molecular formula C9H10O forms 2,4-DNP derivative, reduces Tollens’ reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzenedicarboxylic acid. Identify the compound.

Answer:
Since the given compound with molecular formula C₉H₁₀O form a 2,4-DNP derivative and reduce Tollen’s reagent, it must be an aldehyde. Since it undergoes cannizzaro reaction, therefore CHO group is directly attached to the benzene ring.

Since on vigorous oxidation, it gives 1,2-benzene dicarboxylic acid, therefore it must be ortho-substituted benzaldehyde. The only o-substituted aromatic aldehyde having molecular formula C₉H₁₀O is o—ethyl benzyldehyde all the reaction can show now be explained on the basis of this structure-

Question 49.
An organic compound (A) (molecular formula C₈H₁₆O₂) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) on dehydration gives but-1-ene. Write equations for the reactions involved.

Answer:
Given compound is having 8 carbons, and on reaction with chromic acid C is converted back into B, as chromic acid reaction couldn’t add any carbon hence both alcohol and acid must contain 4 carbons and it is given in the question that on dehydration C will give but-1-ene so alcohol will be butan-1-ol(C) and acid will be butan-1-oic acid(B) and given reaction will be ester hydrolysis,

Question 50.
Arrange the following compounds in increasing order of their property as indicated:

Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert-butyl ketone (reactivity towards HCN)

Answer:
Di-tertbutyl, ketone<methyl, tert-butyl ketone<acetone<acetaldehyde, Di tert butyl is sterically crowded by 2 tert butyl group around Keto group, Methyl tert butyl is also crowded but it is less compared di tert butyl. And acetone has only one Methyl group and acetaldehyde have no group around aldehydic carbon. We know that steric hinderance around active centre reduces reactivity.

Question 51.
Arrange the following compounds in increasing order of their property as indicated:

CH₃CH₂CH(Br)COOH, CH₃CH(Br)CH₂COOH, (CH₃)₂CHCOOH, CH₃CH₂CH₂COOH (acid strength)

Answer:
+I effect donates e^- . Br group will show +I effect along the chain but as I effect is distance dependent effect it will die as the distance increase.+I effect of alkyl group will reduce the acidity of a compound whereas –I effect will increase the acidity,I effects are distance dependent, correct order will be (CH₃)₂CHCOOH< CH₃CH₂CH₂COOH< CH₃CH(Br)CH₂COOH < CH₃CH₂CH(Br)COOH.

Question 52.
Arrange the following compounds in increasing order of their property as indicated:

Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid strength)

Answer:
As we know the electron releasing groups(ERG) reduces the acidic strength of the compound (via inductive effect) whereas the electron withdrawing group(EWG) will increase the acidic strength of compound, and methoxy group is ERG, and nitro group is EWG, Increasing number of EWG will increase the effect and acidity too. Hence final order will be Methoxy benzoic acid< Benzoic acid<4-Nitrobenzoic acid<3,4-Dinitrobenzoic acid.

Question 53.
Give simple chemical tests to distinguish between the following pairs of compounds.

Propanal and Propanone

Answer:
a) Tollen’s test –Due to oxidizing nature of aldehydes they get easily oxidized, wheareas in case of ketones they are not readily
oxidizable. And tollens test exploits this fact, [Ag(NH₃)₂]⁺ is used as reagent Ag mirror is formed during this reaction

b) fehling test- aldehyde reduces the fehling solution to form red brow precipitate of Cu₂O. Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone functiona groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reagent test.

Question 54.
Give simple chemical tests to distinguish between the following pairs of compounds.

Acetophenone and Benzophenone

Answer:
Iodoform test- Methyl ketones give positive iodoform test, so when acetophenone react with NaOI it forms Yellow ppt. of Iodoform. Whereas the benzophenone will not give ppt. of iodoform. Iodoform is CHI₃ tri iodo methane. It forms only in the case when NaOI is trated with methyl ketone.
C₆H₅COCH₃+NaOI → C₆H₅COONa+ CHI₃+NaOH

Question 55.
Give simple chemical tests to distinguish between the following pairs of compounds.

Phenol and Benzoic acid

Answer:
When phenol reacts with FeCl₃ it forms violet coloured complex, whereas the benzoic acid not,

Question 56.
Give simple chemical tests to distinguish between the following pairs of compounds.

Benzoic acid and Ethyl benzoate

Answer:
When we add NaHCO₃ to acid solution it will produce effervescence of CO₂ gas, hence benzoic acid will give CO₂ gas and ethyl benzoate will not.

Question 57.
Give simple chemical tests to distinguish between the following pairs of compounds.

Pentan-2-one and Pentan-3-one

Answer:
Iodoform test – pentan-2-one is methyl ketone it will produce CHI₃ in iodoform test whereas the pentan-3-one will not
Iodoform is CHI₃ tri iodo methane. It forms only in the case when NaOI is trated with methyl ketone, this is confirmatory test for methyl ketones.

Question 58.
Give simple chemical tests to distinguish between the following pairs of compounds.

Benzaldehyde and Acetophenone

Answer:
Iodoform test – as acetophenone is methyl ketone it will form
CHI₃ during iodoform test, Iodoform is CHI₃ tri iodo methane. It forms only in the case when NaOI is trated with methyl ketone, this is confirmatory test for methyl ketones.

Question 59.
Give simple chemical tests to distinguish between the following pairs of compounds.

Ethanal and Propanal

Answer:
Ethanal is methyl aldehyde, it gives positive iodoform test on reacting with NaOI, Whereas the propanal can’t

Question 60.
How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

Methyl benzoate

Answer:
When benzene is treated with Br₂ In presence of ferric bromide (brominating agent) they form bromobenzene. When bromobenzene is treated with Mg in ether it will form Grignard reagent, and if the CO₂ is treated with Grignard reagent (in acidic condition) it will form benzoic acid. After esterification reaction in presence of methanol it will form methyl benzoate.

Question 61.
How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

m-Nitrobenzoic acid

Answer:
When benzene is treated with Br₂ In presence of ferric bromide (brominating agent) they form bromobenzene. When bromobenzene is treated with Mg in ether it will form Grignard reagent, and if the CO₂ is treated with Grignard reagent (in acidic condition) it will form benzoic acid. When nitrating mixture is treated with benzoic acid it will form m-Nitrobenzoic acid.

Question 62.
How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

p-Nitrobenzoic acid

Answer:
after friedel craft acylation of benzene it will form toluene, after nitration it forms p-nitro toluene as major product, after oxidation of this compound with KMnO₄ in acidic conditions it forms p-Nitrobenzoic acid.

Question 63.
How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

Phenylacetic acid

Answer:
after friedel craft acylation of benzene it will form toluene, after bromination with NBS it forms benzyl bromide, when benzyl bromide reacts with Alc.KCN benzyl cyanide forms . Acidic hydration it forms phenylacetic acid.

Question 64.
How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

p-Nitrobenzaldehyde.

Answer:
after friedel craft acylation of benzene it will form toluene, after nitration it forms p-nitro toluene as major product. After reacting it with chromyl chloride it will forms chromyl complex. When this complex treated under acidic condition it forms p-nitro benzaldehyde,

Question 65.
How will you bring about the following conversions in not more than two steps?

Propanone to Propene

Answer:
When propanone reacts with NaBH₄ it will form propan-2-ol.This alcohol is dehydrated to form propene.

Question 66.
How will you bring about the following conversions in not more than two steps?

Benzoic acid to Benzaldehyde

Answer:
When benzoic acid is treated with SOCl₂ it chlorinates the acid. After controlled hydrogenation it forms benzaldehyde.

Question 67.
How will you bring about the following conversions in not more than two steps?

Ethanol to 3-Hydroxybutanal

Answer:
When ethanol is treated with Cu at 573 k, it will oxidize to ethanal. When ethanal is treated with Dil.NaOH it will form 3-Hydroxy butanal

Question 68.
How will you bring about the following conversions in not more than two steps?

Benzene to m-Nitroacetophenone

Answer:
After frieadal craft acylation of benzene it will convert into acyl benzene. And further treating with nitrating mixture it forms m-nitroaceto phenone .

Question 69.
How will you bring about the following conversions in not more than two steps?

Benzaldehyde to Benzophenone

Answer:
When benzaldehyde is oxidized with dichromate and treated with calcium carbonate it forms calcium salt. And after dry distillation it gets converted into benzophenone.

Question 70.
How will you bring about the following conversions in not more than two steps?

Bromobenzene to 1-Phenylethanol

Answer:
when bromobenzene reacts with Mg in dry ether it forms Grignard reagent, further treating with ethanal in acidic condition it forms 1-phenyl ethanol.

Question 71.
How will you bring about the following conversions in not more than two steps?

Benzaldehyde to 3-Phenylpropan-1-ol

Answer:
When benzaldehyde is mixed with ethanal in presence of Dil. NaOH and then heating it in acidic condition, and after that hydrogenation it forms 3-phenylpropan-1-ol.

Question 72.
How will you bring about the following conversions in not more than two steps?

Benazaldehyde to α-Hydroxyphenylacetic acid

Answer:
benzaldehyde is mixed with HCN at pH 9-10, and further treating it with Water at slightly acidic condition it forms α-Hydroxyphenylacetic acid

Question 73.
How will you bring about the following conversions in not more than two steps?

Benzoic acid to m- Nitrobenzyl alcohol

Answer:
When benzoic acid reacted with nitrating mixture it forms m- nitrobenzoic acid further it treated with SOCl₂ it chlorinate the acidic COOH group. And reacting with NaBH₄ further it get converted into m-nitroenzyl alcohol.

Question 74.
Describe the following:

Acetylation-

Answer:
Acetylation refers to the process of introducing an acetyl group (resulting in an acetoxy group) into a compound, namely the substitution of an acetyl group for an active hydrogen atom. A reaction involving the replacement of the hydrogen atom of a hydroxyl group with an acetyl group (CH₃CO) yields a specific ester, the acetate. Acetic anhydride is commonly used as an acetylating agent reacting with free hydroxyl groups., this reaction is usually carried out in the presence of base like pyridine.

Question 75.
Describe the following:

Cannizzaro reaction

Answer:
Aldeydes having no α-H undergo the disproportion reaction in the presence of Strong alkali, it is a chemical reaction that involves the base-induced disproportionation of a non-enolizable aldehyde This reaction is known as Cannizzaro reaction.In this reaction two molecules of aldehyde is reacted, 1 is reduced to alcohol and other is oxidized to carboxylic acid.

Question 76.
Describe the following:

Cross aldol condensation

Answer:
When aldol condensation is carried out between two different aldehydes or two different ketones,or one aldehyde and one ketone this reaction is called as CROSS ALDOL CONDENSATION, if both the reactant is having α H then 4 products are formed ( 2 self aldol& 2 cross aldol)

Question 77.
Describe the following:

Decarboxylation

Answer:

Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO₂). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. in this reaction carbon dioxide is released.

Question 78.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When 1- phenyl ethane is oxidized with a strong oxidizing agent like KMnO₄, it forms a benzoic acid ion.

Question 79.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When phthalic acid is treated with SoCl₂ it chlorinates both carboxyl group to form ptthaloyl chloride.

Question 80.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When benzaldehyde is treated with semicarbazide to form benzaldehyde semicarbazone.

Question 81.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When benzene is mixed with benzoyl chloride in presence of Anhyd.AlCl₃ to give benzophenone.

Question 82.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
when 4-oxocyclohexanecarbeldehyde is treated with tollens reagent it gets oxidized to carboxylate anion . as it is aldehyde it reduces tollens reagent.

Question 83.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When 2-formyl benzoic acid is treated with NaCN it produces 2-[1-hydroxycyanomethyl]benzoic acid.

Question 84.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When benzaldehyde and propanal mixed equally in presence of Dil.NaOH it forms 2-methyl-3-phenyl-prop-2-enal.

Question 85.
Complete each synthesis by giving missing starting material, reagent or products

CH₃COCH₂COOC₂H₅

Answer:
When Ethyl 3-oxobutanate is treated with sodium borohydride it converts oxo to hydroxyl.

Question 86.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When cyclohexanol is oxidized with CrO₃ it forms cyclohexanone.

Question 87.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When methylenecyclohexane undergo hydroboration oxidation reaction it will form alcohol. Further treating with oxidizing agent PCC it converts into aldehyde.

Question 88.
Complete each synthesis by giving missing starting material, reagent or products

Answer:
When cyclohexylidenecyclohexane undergo ozonolysis it will form cyclohexanone.

Question 89.
Give plausible explanation for each of the following:

Cyclohexanone forms cyanohydrin in good yield but 2,2,6-trimethylcyclohexanone does not.

Answer:
cyclohexanone forms cyanohydrin in good yield because the ketonic group has very less steric hindrance at both the ortho position but 2,2,6 tri methyl cyclohexanone have high steric hindrance which reduces the attack from CN nucleophile.

(High steric hindrance)

Question 90.
Give plausible explanation for each of the following:

There are two –NH₂ groups in semicarbazide. However, only one is involved in the formation of semicarbazones.

Answer:
Only one Amino group is involved in the resonance structure of semicarbazide hence e^- density on NH₂ group decreases & it can’t act as a nucleophile. But another NH₂ group can attack as a nucleophile to form semicarbazones.

Question 91.
Give plausible explanation for each of the following:

During the preparation of esters from a carboxylic acid and an alcohol in the presence of an acid catalyst, the water or the ester should be removed as soon as it is formed.

Answer:
It is the reversible reaction hence if we don’t remove the water or ester the reaction may proceed in backward direction, for that It is essential the water or ester as soon as formed.

Question 92.
An organic compound contains 69.77% carbon, 11.63% hydrogen and rest oxygen.

The molecular mass of the compound is 86. It does not reduce Tollens’ reagent but forms an addition compound with sodium hydrogensulphite and give positive iodoform test. On vigorous oxidation it gives ethanoic and propanoic acid. Write the possible structure of the compound.

Answer:
C = 69.77% ie ==5.88;
H=11.63% ie==11.63;

O=(100-(69.77+11.63))=18.6% ie==1.16

Molecular Ratio will be 5.88:11.63:1.16=5:10:1.

Empirical formula is C₅H₁₀O, molecular weight will be =86.

Hence molecular formula will be same.

It does not reduce tollen’s reagent, it is not an aldehyde. The compound is addition product of sodium hydrogen sulphite it must be a ketone, It is giving positive iodoform test it is ethyl ketone. On vigorous oxidation, it forms ethanoic acid and propanoic acid the given compound is pentane-2-one.

Question 93.
Although phenoxide ion has more number of resonating structures than carboxylate ion, the carboxylic acid is a stronger acid than phenol. Why?

Answer:
Resonating structures of phenoxide are-

In structure I and V –ve charge is on E.N. Oxygen, in other cases, it is on Less E.N Carbon hence they contribute less towards stability. And the –ve charge is localized.

Resonating structures of carboxylic acid-

Both the structures have –ve charge on oxygen and electron are delocalised too hence, the carboxylic acid is more stable and acidic than phenol.