Class 10th Science Gujarat Board Solution
Exercise- Which is the primary state in transformation of coal?A. Lignite B. Bitumen C. Anthracite…
- What is the matured form of coal?A. Lignite B. Bitumen C. Anthracite D. Peat…
- Which type of coal does not produce smoke or odour when burnt?A. Anthracite B. Lignite C.…
- Which of the following components is not obtained when destructive distillation of mineral…
- Which of the following is used in production of water gas ?A. Coke B. Coaltar C. Coal gas…
- Water gas is the mixture of which gases?A. Carbon dioxide and hydrogen B. Carbon and…
- Which gas is filled at high pressure in cylinders of household cooking gas ?A. Methane B.…
- Which component obtained from refining of petroleum is used as solvent in…
- Which of the following is used in petromax to obtain light?A. Petrol B. Ethane C. Propane…
- Which is the chief hydrocarbon in natural gas?A. Methane B. Ethane C. Propane D. Butane…
- What is the molecular formula of ethane?A. C2H6 B.C2H2 C. C2H2 D.CH4…
- What is the general formula of ethane?A. CnH2n B.CnH2n-2 C. CnH2n+2 D. CnHn…
- What is the commercial name of ethyne?A. Acrylic acid B. Acetylene C. Ethane D.…
- C3H8 is the molecular formula of which compound?A. Methane B. Ethane C. Propane D. Butane…
- What is the angle between any two bonds in methane molecule?A. 105o54’ B. 109o28’ C.…
- What is called fossil fuel ?A. Mineral coal B. Wood C. Cowdung cake D. All the given…
- From where mineral coal is obtained in Gujarat?A. Ankleshwar B. Cambay (Khambhat) C.…
- What is used as fuel in jet planes?A. Gasolene B. Diesel oil C. kerosene D. All the given…
- What is called fossil fuel and write its use.
- How many main types of mineral coal are three and which are they?…
- Write a short note on coke.
- Explain in brief about coal tar and coal gas.
- What is the valency of carbon? Why?
- What is meant by hydrocarbon ? How are they classified?
- Explain by drawing the shape of methane molecule.
- From which methane is obtained? Write its preparation.
- Write uses of ethyne by writing its common name and structural formula.…
- What is isomerism? Write isomers of butane and pentane.
- The everyday life is not possible without mineral coal and petroleum. Why ?…
- Explain cracking reaction.
- Explain the destructive distillation of mineral coal in laboratory by drawing its figure.…
- Write the types of mineral, coal, explain that the use of anthracite coal is more than the…
- Explain occurrence of methane and its preparation.
- Writing the common molecular formulas of alkanes, and alkynes, write the names of first…
- Explain preparation of ethene in laboratory by drawing figure.
- Explain preparation of ethyne in laboratory by drawing figure.
- What is meant by hydrocarbons ? Explain its classification in detail.…
- Explain in detail about natural gas.
- What is meant by petroleum ? Explain in detail the refining of petroleum.…
- Which is the primary state in transformation of coal?A. Lignite B. Bitumen C. Anthracite…
- What is the matured form of coal?A. Lignite B. Bitumen C. Anthracite D. Peat…
- Which type of coal does not produce smoke or odour when burnt?A. Anthracite B. Lignite C.…
- Which of the following components is not obtained when destructive distillation of mineral…
- Which of the following is used in production of water gas ?A. Coke B. Coaltar C. Coal gas…
- Water gas is the mixture of which gases?A. Carbon dioxide and hydrogen B. Carbon and…
- Which gas is filled at high pressure in cylinders of household cooking gas ?A. Methane B.…
- Which component obtained from refining of petroleum is used as solvent in…
- Which of the following is used in petromax to obtain light?A. Petrol B. Ethane C. Propane…
- Which is the chief hydrocarbon in natural gas?A. Methane B. Ethane C. Propane D. Butane…
- What is the molecular formula of ethane?A. C2H6 B.C2H2 C. C2H2 D.CH4…
- What is the general formula of ethane?A. CnH2n B.CnH2n-2 C. CnH2n+2 D. CnHn…
- What is the commercial name of ethyne?A. Acrylic acid B. Acetylene C. Ethane D.…
- C3H8 is the molecular formula of which compound?A. Methane B. Ethane C. Propane D. Butane…
- What is the angle between any two bonds in methane molecule?A. 105o54’ B. 109o28’ C.…
- What is called fossil fuel ?A. Mineral coal B. Wood C. Cowdung cake D. All the given…
- From where mineral coal is obtained in Gujarat?A. Ankleshwar B. Cambay (Khambhat) C.…
- What is used as fuel in jet planes?A. Gasolene B. Diesel oil C. kerosene D. All the given…
- What is called fossil fuel and write its use.
- How many main types of mineral coal are three and which are they?…
- Write a short note on coke.
- Explain in brief about coal tar and coal gas.
- What is the valency of carbon? Why?
- What is meant by hydrocarbon ? How are they classified?
- Explain by drawing the shape of methane molecule.
- From which methane is obtained? Write its preparation.
- Write uses of ethyne by writing its common name and structural formula.…
- What is isomerism? Write isomers of butane and pentane.
- The everyday life is not possible without mineral coal and petroleum. Why ?…
- Explain cracking reaction.
- Explain the destructive distillation of mineral coal in laboratory by drawing its figure.…
- Write the types of mineral, coal, explain that the use of anthracite coal is more than the…
- Explain occurrence of methane and its preparation.
- Writing the common molecular formulas of alkanes, and alkynes, write the names of first…
- Explain preparation of ethene in laboratory by drawing figure.
- Explain preparation of ethyne in laboratory by drawing figure.
- What is meant by hydrocarbons ? Explain its classification in detail.…
- Explain in detail about natural gas.
- What is meant by petroleum ? Explain in detail the refining of petroleum.…
Exercise
Question 1.Which is the primary state in transformation of coal?
A. Lignite
B. Bitumen
C. Anthracite
D. Peat
Answer:Peat is the most basic form of coal containing 26% carbon and is the primary state of transformation of coal from wood.
Question 2.What is the matured form of coal?
A. Lignite
B. Bitumen
C. Anthracite
D. Peat
Answer:Anthracite is the matured form of coal and contains 94% to 98% of coal. It a also contains small amount of volatile matter and moisture as well. Its heat energy is about 33kJg-1.When pure anthracite is burned it produces very little amount of smoke or smell and also leaves very less amount of residue.
Question 3.Which type of coal does not produce smoke or odour when burnt?
A. Anthracite
B. Lignite
C. Bitumen
D. Peat
Answer:Anthracite is considered as one of the finest quality or matured form of coal and it contains also very high proportion of carbon in it almost 94% to 98%.Hence, it does not produce smoke or odour when burnt.
Question 4.Which of the following components is not obtained when destructive distillation of mineral coal is carried out ?
A. Coal gas
B. Methane
C. Coaltar
D. Coke
Answer:Coal gas, Coke and Coal tar are obtained in the process of destructive distillation of mineral coal but methane is not obtained during this process. Hence, the correct option is B.
Question 5.Which of the following is used in production of water gas ?
A. Coke
B. Coaltar
C. Coal gas
D. Ammonia
Answer:Coke is used during the production of water gas. Coke is used as a smokeless fuel in the production of water gas. The mixture of carbon monoxide and hydrogen gas is obtained when water vapour is passed over hot coke. It is called water gas.
C + H2O → ( CO + H2 )
Question 6.Water gas is the mixture of which gases?
A. Carbon dioxide and hydrogen
B. Carbon and hydrogen
C. Carbon monoxide and hydrogen
D. Ammonia and hydrogen
Answer:A mixture of carbon monoxide and hydrogen gas is obtained when water vapour is passed over hot coke. It is called water gas.
Question 7.Which gas is filled at high pressure in cylinders of household cooking gas ?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer:Butane is filled at high pressure in cylinders of household cooking gas. To detect leakage of the gas from the cylinder methyl mercaptan having a very bad smell is added to it.
Question 8.Which component obtained from refining of petroleum is used as solvent in petrochemicals?
A. Naphtha
B. Kerosene
C. Tar
D. Petroleum coke
Answer:Naphtha is the component obtained from refining of petroleum which is used as solvent in petrochemicals. Naphtha compounds contains 8 to 10 carbon atoms are obtained at the temperature of 393K to 453K in the fractional distillation process.
Question 9.Which of the following is used in petromax to obtain light?
A. Petrol
B. Ethane
C. Propane
D. Butane
Answer:Petrol is used in petromax to obtain light.
Question 10.Which is the chief hydrocarbon in natural gas?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer:the chief hydrocarbon in natural gas is Methane. In gaseous hydrocarbons like ethane, propane and butane are also present in it as constituents but mostly natural gas contains methane.
Question 11.What is the molecular formula of ethane?
A. C2H6
B.C2H2
C. C2H2
D.CH4
Answer:The molecular formula of ethane is C2H6. Ethane belongs to the alkane homologous series which is represented by the formula CnH2n+2. Ethane is the second member of the series and hence its formula is obtained by substituting 2 in place of n in the general formula to obtain C2H6.
Question 12.What is the general formula of ethane?
A. CnH2n
B.CnH2n-2
C. CnH2n+2
D. CnHn
Answer:Ethane belongs to the alkane homologous series which is represented by the general molecular formula CnH2n+2.
Question 13.What is the commercial name of ethyne?
A. Acrylic acid
B. Acetylene
C. Ethane
D. Oxyacetylene
Answer:Ethyne is a very important industrial compound. The commercial name of ethyne is acetylene. Substances like ethanol, acetic acid, vinyl polymer and plastics are prepared from ethyne.
Question 14.C3H8 is the molecular formula of which compound?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer:We can clearly see that 8 = 2 X 3 + 2.
Hence, C3H8 belongs to the alkane series. Now, as it contains 3 carbon atoms so its name is Propane.
Question 15.What is the angle between any two bonds in methane molecule?
A. 105o54’
B. 109o28’
C. 119o28’
D. 190o28’
Answer:Methane molecules belongs to the alkane series in which all the hydrogen atoms are attached to carbon by single bond forming a tetrahedral shape with the angle between any two bonds in methane molecule being 109o28’.
Question 16.What is called fossil fuel ?
A. Mineral coal
B. Wood
C. Cowdung cake
D. All the given
Answer:Fossil means something obtained from the dead remains. Coal is obtained from the fossils of plants and animals. Hence, mineral coal is called fossil fuel.
Question 17.From where mineral coal is obtained in Gujarat?
A. Ankleshwar
B. Cambay (Khambhat)
C. Thangadh
D. kalol
Answer:Mineral coal is obtained from Thangadh in Gujarat.
Question 18.What is used as fuel in jet planes?
A. Gasolene
B. Diesel oil
C. kerosene
D. All the given
Answer:Gasolene is used as fuel in jet planes. It has a boiling range of 343 to 473 K. It contains chains having 5 to 12 carbon atoms in it.
Question 19.What is called fossil fuel and write its use.
Answer:Fossil fuel is the fuel obtained from the decomposition of plants and animals died crores of years ago and buried deep inside the surface of the earth. In the crust at high temperature and pressure the components of plants and animals gets converted into fuel known as fossil fuel.
Fossil fuels like mineral coal, petroleum and natural gas find extensive use in our modern world. They are used to fuel up our automobiles, to heat our homes, power industry and manufacturing, provide us with electricity their derivatives are used for medical purpose, as cosmetics, wax, mould, plastics, synthetic fabrics ,lubricants, fuel in our kitchens as cooking gas, manufacture of synthetic rubber, dyes, solvents, pesticides, etc.
Question 20.How many main types of mineral coal are three and which are they?
Answer:There are four main types of mineral coal. These are : -
a. Peat
Peat contain about 28% of Carbon. It is the primary state of transformation of coal from wood. It is known as rough coal. Wax, acetone, acetic acid, methanol, many cyclic organic compounds are obtained by fractional distillation of peat.
b. Lignite
It contains about 28 to 30% carbon along with volatile matter and moisture. The heat energy of lignite is 27kJg-1. It is used mostly in railways, thermal power and small and big industries. It is used to obtain coal gas and coal tar.
c. Bituminous coal.
It contains about 78 to 86% of carbon content. It also contains volatile matter and moisture . Its heat energy is about 30kJg-1. It is used as fuel in the production of steel and to generate electricity.
d. Anthracite
It is the highest quality of coal, containing 94 to 98% of carbon. It contains small quantity of moisture and volatile matter. Its heat energy is 33kJg-1. When pure anthracite is burnt smoke and smell is not produced and the amount of residue is very less.
Question 21.Write a short note on coke.
Answer:•Coke is a fuel with a high carbon content and few impurities, usually made from coal.
•It is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulphur bituminous coal.
•Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace.
•The carbon monoxide produced by its combustion reduces iron oxide (hematite) in the production of the iron product.
•Coke is commonly used as fuel for blacksmithing.
•It is used as fuel in stoves and furnaces.
Question 22.Explain in brief about coal tar and coal gas.
Answer:Coal tar.
It is a dark black coloured liquid, mostly various types of organic compounds are present in it. Earlier it was used for the preparation of explosives, dyes, artificial fibres, drugs, pesticides. Now a days organic substances are obtained from petroleum products instead of coal tar.
Coal gas:
mostly carbon monoxide and some other gaseous hydrocarbon compounds that are present in coal gas. This mixture of gases is combustible and is used as fuel.
Question 23.What is the valency of carbon? Why?
Answer:The valency of carbon is 4.
Carbon is having 4 electrons in its outermost shell which is the 2nd shell. It can use all of these 4 electrons to form bonds with other substances and itself. Hence, the valency off carbon is taken as 4.
Question 24.What is meant by hydrocarbon ? How are they classified?
Answer:Hydrocarbons: These are those class of compounds in chemistry which contains only carbon and hydrogen as elements in their molecular formula and structure.
They are classified on the basis of number of covalent bonds between carbon carbon atoms as : -
a. Saturated hydrocarbon:
In this all the four valences if carbon are completed by covalent single bond with other atoms.
b. Unsaturated hydrocarbon:
In this the two carbon atoms are combined by double or triple bond.
Question 25.Explain by drawing the shape of methane molecule.
Answer:Methane is a saturated hydrocarbon and belongs to the alkane homologous series which is represented by the formula CnH2n+2.
All four of its valences are satisfied by single bonds with hydrogen atom giving a tetrahedral shape with the angle between any two bonds in methane molecule being 109o28’.
Question 26.From which methane is obtained? Write its preparation.
Answer:Methane is obtained from the marsh gas available from the mines of mineral coal and gas collected over petroleum in the sedimentary rocks in the crust of the earth. Methane I also present in dung, excretion of animals, gobar gas, sewage gas and biogas obtained from decomposition of plant and animal waste.
Methane gas is obtained by heating sodium acetate and soda lime.
CH3COONa + CaO + NaOH → CH4 + Na2CO3
Question 27.Write uses of ethyne by writing its common name and structural formula.
Answer:Common name : Acetylene
Structural formula :
Uses of ethyne
It is used for the preparation of ethanol, acetic acid, vinyl polymer and plastic like substances. It is used in oxyacetylene flame used for welding metals. It is filled in rubber gas balloons which are flown high in the sky.
Question 28.What is isomerism? Write isomers of butane and pentane.
Answer:Isomerism:
Organic compounds having the same molecular formula but different structural formula are called isomers and this phenomenon is called isomerism.
Butane isomers are :
Pentane isomers are :
Question 29.The everyday life is not possible without mineral coal and petroleum. Why ?
Answer:Almost everything that we use in our daily life ranging from cosmetics, wax , mould, plastics, synthetic fabrics ,lubricants, fuel in our kitchens as cooking gas, manufacture of synthetic rubber, dyes, solvents, pesticides, to running automobiles and drawing power is derived from mineral coal or petroleum. Hence without mineral coal and petroleum our life would come to a deadly stop.
Question 30.Explain cracking reaction.
Answer:Cracking reaction
In this big molecules break into smaller molecules.
Question 31.Explain the destructive distillation of mineral coal in laboratory by drawing its figure.
Answer:Destructive distillation of mineral coal in laboratory :
Mineral coal is taken in a hard glass test tube. In a second test tube some water is taken. The apparatus is arranged as shown in the figure:
The coal is heated in a Bunsen burner and the gas coming out is passed through water in the other test tube. Sometimes later deposition of coal tar would be found in the test tube containing water. A gas will come out through the tube connected with the upper part of the test tube. This gas is called coal gas. Now the portion left out in the tube containing mineral coal is called coke.
Question 32.Write the types of mineral, coal, explain that the use of anthracite coal is more than the bitumen coal. Why?
Answer:There are four main types of mineral coal. These are : -
a. Peat
Peat contains about 28% of Carbon. It is the primary state of transformation of coal from wood. It is known as rough coal. Wax, acetone, acetic acid, methanol, many cyclic organic compounds are obtained by fractional distillation of peat.
b. Lignite
It contains about 28 to 30% carbon along with volatile matter and moisture. The heat energy of lignite is 27kJg-1. It is used mostly in railways, thermal power and small and big industries. It is used to obtain coal gas and coal tar.
c. Bituminous coal.
It contains about 78 to 86% of carbon content. It also contains volatile matter and moisture. Its heat energy is about 30kJg-1. It is used as fuel in the production of steel and to generate electricity.
d. Anthracite
It is the highest quality of coal, containing 94 to 98% of carbon. It contains a small quantity of moisture and volatile matter. Its heat energy is 33kJg-1. When pure anthracite is burnt smoke and smell is not produced and the amount of residue is very less.
The use of anthracite coal is more than the bitumen coal because the carbon content in anthracite coal is more than the carbon content in the bitumen coal. Also when pure anthracite is burnt smoke and smell is not produced and the amount of residue is very less. Hence, it is very much environment-friendly and saves a lot of money that could have been used in the process of waste disposal.
Question 33.Explain occurrence of methane and its preparation.
Answer:Occurrence of methane
Methane is obtained from the marsh gas available from the mines of mineral coal and gas collected over petroleum in the sedimentary rocks in the crust of the earth. Methane I also present in dung, excretion of animals, gobar gas, sewage gas and biogas obtained from the decomposition of plant and animal waste.
Preparation of methane
Methane gas is obtained by heating sodium acetate and soda lime.
CH3COONa + CaO + NaOH → CH4 + Na2CO3
Question 34.Writing the common molecular formulas of alkanes, and alkynes, write the names of first compound of each.
Answer:The common molecular formula of : -
Alkane is – CnH2n+2
Alkyne is - CnH2n-2
The names of first compound of alkaneis – methane.
The names of first compound of alkyneis – ethyne.
Question 35.Explain preparation of ethene in laboratory by drawing figure.
Answer:Preparation of ethene in laboratory is as follows : -
At first take a hard glass test tube and in it put 3ml of melted wax and one tea spoon of sand. Then some porcelain is inserted in the front part of the test tube. The arrangement is made as shown in the following figure:
The test tube is then heated on a spirit lamp until the pieces of porcelain become red hot and then immediately heat the sand containing wax. Continue the heating process alternatively between the porcelain and the sand. When alkene vapours from wax pass through the heated porcelain ethane gas is liberated by cracking The gas is collected in a jar by downward displacement of water.
Question 36.Explain preparation of ethyne in laboratory by drawing figure.
Answer:Preparation of ethyne in laboratory is as follows : -
Take two to three small pieces of calcium carbide in a conical flask. The conical flask is arranged as shown in the figure below:-
Now as we add water through the thistle funnel, a chemical reaction takes place and ethyne is produced which could be collected in a jar by downward displacement of water.
Question 37.What is meant by hydrocarbons ? Explain its classification in detail.
Answer:Hydrocarbons: These are the category of compounds in chemistry which contains only carbon and hydrogen as elements in their molecular formula and structure.
These are classified on the basis of number of covalent bonds between carbon carbon atoms as: -
a. Saturated hydrocarbon:
In this all the four valences if carbon are completed by covalent single bond with other atoms.
b. Unsaturated hydrocarbon:
In this the two carbon atoms are combined by double or triple bond.
Question 38.Explain in detail about natural gas.
Answer:•Natural gas is collected over the petroleum in the rocks. The gas which is available with petroleum is called natural gas.
•It is obtained as an oily liquid along with petroleum or independently in the gaseous form. While drilling in the earth’s crust natural gas is obtained first followed by the petroleum.
•In natural gas the main hydrocarbon which is present is called methane . It also contains some other gaseous hydrocarbons like ethane, propane and butane with it.
•It is very easy to transport through gas pipelines and is widely used as a fuel in household uses in urban cities.
•It is also used as fuel to power thermal power plants to produce electricity.
Question 39.What is meant by petroleum ? Explain in detail the refining of petroleum.
Answer:Petroleum: Petroleum is defined as the mineral oil that has been originated from the fossils of plants and animal kingdoms buried under the surface of sea in prehistoric times.
Refining of petroleum:
•The impure oil which is available from the wells is transported to the refinery for purification by pipelines or by tankers. The natural gas is separated from it in the initial stage. The oil is allowed to settle in many large tanks in the refinery and the wastewater is separated.
•Then the fractional distillation of the oil is being carried out. In distillation, hydrocarbons are separated in fractions having specific useful properties for the industries. Each of these fractions is being distilled at a definite range of temperature, and it is a mixture of certain compounds. A typical distillation tower is as shown below: -
•
•Here petroleum is heated in a furnace and then sent to a fractionating column in the vapour form. The column is 2 to 4 meter in diameter and 30 to 60 meter high. Perforated shelves are fixed in it, and on each of these shelves, there is a cover like a cap.
•The substances which do not distill are collected at the lower part of the column. The vapour petroleum gets cooled while going up in the column and falls down in the form of liquid.
•The vapour passed through the liquid is collected on the shelves. Thus substances having higher boiling points come down in the form of the liquid and the substances having lower boiling point go up in the form of the vapour.
•In this way distillation continues near each shelf where compounds having nearby boiling points are separated.
•Here substances having a lower boiling point are collected in the shelves of the upper part while those having lower point are collected in the shelves of the lower part. The number and distance of the shelves are so arranged that a certain fraction is collected in the shelves at a certain height.
Which is the primary state in transformation of coal?
A. Lignite
B. Bitumen
C. Anthracite
D. Peat
Answer:
Peat is the most basic form of coal containing 26% carbon and is the primary state of transformation of coal from wood.
Question 2.
What is the matured form of coal?
A. Lignite
B. Bitumen
C. Anthracite
D. Peat
Answer:
Anthracite is the matured form of coal and contains 94% to 98% of coal. It a also contains small amount of volatile matter and moisture as well. Its heat energy is about 33kJg-1.When pure anthracite is burned it produces very little amount of smoke or smell and also leaves very less amount of residue.
Question 3.
Which type of coal does not produce smoke or odour when burnt?
A. Anthracite
B. Lignite
C. Bitumen
D. Peat
Answer:
Anthracite is considered as one of the finest quality or matured form of coal and it contains also very high proportion of carbon in it almost 94% to 98%.Hence, it does not produce smoke or odour when burnt.
Question 4.
Which of the following components is not obtained when destructive distillation of mineral coal is carried out ?
A. Coal gas
B. Methane
C. Coaltar
D. Coke
Answer:
Coal gas, Coke and Coal tar are obtained in the process of destructive distillation of mineral coal but methane is not obtained during this process. Hence, the correct option is B.
Question 5.
Which of the following is used in production of water gas ?
A. Coke
B. Coaltar
C. Coal gas
D. Ammonia
Answer:
Coke is used during the production of water gas. Coke is used as a smokeless fuel in the production of water gas. The mixture of carbon monoxide and hydrogen gas is obtained when water vapour is passed over hot coke. It is called water gas.
C + H2O → ( CO + H2 )
Question 6.
Water gas is the mixture of which gases?
A. Carbon dioxide and hydrogen
B. Carbon and hydrogen
C. Carbon monoxide and hydrogen
D. Ammonia and hydrogen
Answer:
A mixture of carbon monoxide and hydrogen gas is obtained when water vapour is passed over hot coke. It is called water gas.
Question 7.
Which gas is filled at high pressure in cylinders of household cooking gas ?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer:
Butane is filled at high pressure in cylinders of household cooking gas. To detect leakage of the gas from the cylinder methyl mercaptan having a very bad smell is added to it.
Question 8.
Which component obtained from refining of petroleum is used as solvent in petrochemicals?
A. Naphtha
B. Kerosene
C. Tar
D. Petroleum coke
Answer:
Naphtha is the component obtained from refining of petroleum which is used as solvent in petrochemicals. Naphtha compounds contains 8 to 10 carbon atoms are obtained at the temperature of 393K to 453K in the fractional distillation process.
Question 9.
Which of the following is used in petromax to obtain light?
A. Petrol
B. Ethane
C. Propane
D. Butane
Answer:
Petrol is used in petromax to obtain light.
Question 10.
Which is the chief hydrocarbon in natural gas?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer:
the chief hydrocarbon in natural gas is Methane. In gaseous hydrocarbons like ethane, propane and butane are also present in it as constituents but mostly natural gas contains methane.
Question 11.
What is the molecular formula of ethane?
A. C2H6
B.C2H2
C. C2H2
D.CH4
Answer:
The molecular formula of ethane is C2H6. Ethane belongs to the alkane homologous series which is represented by the formula CnH2n+2. Ethane is the second member of the series and hence its formula is obtained by substituting 2 in place of n in the general formula to obtain C2H6.
Question 12.
What is the general formula of ethane?
A. CnH2n
B.CnH2n-2
C. CnH2n+2
D. CnHn
Answer:
Ethane belongs to the alkane homologous series which is represented by the general molecular formula CnH2n+2.
Question 13.
What is the commercial name of ethyne?
A. Acrylic acid
B. Acetylene
C. Ethane
D. Oxyacetylene
Answer:
Ethyne is a very important industrial compound. The commercial name of ethyne is acetylene. Substances like ethanol, acetic acid, vinyl polymer and plastics are prepared from ethyne.
Question 14.
C3H8 is the molecular formula of which compound?
A. Methane
B. Ethane
C. Propane
D. Butane
Answer:
We can clearly see that 8 = 2 X 3 + 2.
Hence, C3H8 belongs to the alkane series. Now, as it contains 3 carbon atoms so its name is Propane.
Question 15.
What is the angle between any two bonds in methane molecule?
A. 105o54’
B. 109o28’
C. 119o28’
D. 190o28’
Answer:
Methane molecules belongs to the alkane series in which all the hydrogen atoms are attached to carbon by single bond forming a tetrahedral shape with the angle between any two bonds in methane molecule being 109o28’.
Question 16.
What is called fossil fuel ?
A. Mineral coal
B. Wood
C. Cowdung cake
D. All the given
Answer:
Fossil means something obtained from the dead remains. Coal is obtained from the fossils of plants and animals. Hence, mineral coal is called fossil fuel.
Question 17.
From where mineral coal is obtained in Gujarat?
A. Ankleshwar
B. Cambay (Khambhat)
C. Thangadh
D. kalol
Answer:
Mineral coal is obtained from Thangadh in Gujarat.
Question 18.
What is used as fuel in jet planes?
A. Gasolene
B. Diesel oil
C. kerosene
D. All the given
Answer:
Gasolene is used as fuel in jet planes. It has a boiling range of 343 to 473 K. It contains chains having 5 to 12 carbon atoms in it.
Question 19.
What is called fossil fuel and write its use.
Answer:
Fossil fuel is the fuel obtained from the decomposition of plants and animals died crores of years ago and buried deep inside the surface of the earth. In the crust at high temperature and pressure the components of plants and animals gets converted into fuel known as fossil fuel.
Fossil fuels like mineral coal, petroleum and natural gas find extensive use in our modern world. They are used to fuel up our automobiles, to heat our homes, power industry and manufacturing, provide us with electricity their derivatives are used for medical purpose, as cosmetics, wax, mould, plastics, synthetic fabrics ,lubricants, fuel in our kitchens as cooking gas, manufacture of synthetic rubber, dyes, solvents, pesticides, etc.
Question 20.
How many main types of mineral coal are three and which are they?
Answer:
There are four main types of mineral coal. These are : -
a. Peat
Peat contain about 28% of Carbon. It is the primary state of transformation of coal from wood. It is known as rough coal. Wax, acetone, acetic acid, methanol, many cyclic organic compounds are obtained by fractional distillation of peat.
b. Lignite
It contains about 28 to 30% carbon along with volatile matter and moisture. The heat energy of lignite is 27kJg-1. It is used mostly in railways, thermal power and small and big industries. It is used to obtain coal gas and coal tar.
c. Bituminous coal.
It contains about 78 to 86% of carbon content. It also contains volatile matter and moisture . Its heat energy is about 30kJg-1. It is used as fuel in the production of steel and to generate electricity.
d. Anthracite
It is the highest quality of coal, containing 94 to 98% of carbon. It contains small quantity of moisture and volatile matter. Its heat energy is 33kJg-1. When pure anthracite is burnt smoke and smell is not produced and the amount of residue is very less.
Question 21.
Write a short note on coke.
Answer:
•Coke is a fuel with a high carbon content and few impurities, usually made from coal.
•It is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulphur bituminous coal.
•Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace.
•The carbon monoxide produced by its combustion reduces iron oxide (hematite) in the production of the iron product.
•Coke is commonly used as fuel for blacksmithing.
•It is used as fuel in stoves and furnaces.
Question 22.
Explain in brief about coal tar and coal gas.
Answer:
Coal tar.
It is a dark black coloured liquid, mostly various types of organic compounds are present in it. Earlier it was used for the preparation of explosives, dyes, artificial fibres, drugs, pesticides. Now a days organic substances are obtained from petroleum products instead of coal tar.
Coal gas:
mostly carbon monoxide and some other gaseous hydrocarbon compounds that are present in coal gas. This mixture of gases is combustible and is used as fuel.
Question 23.
What is the valency of carbon? Why?
Answer:
The valency of carbon is 4.
Carbon is having 4 electrons in its outermost shell which is the 2nd shell. It can use all of these 4 electrons to form bonds with other substances and itself. Hence, the valency off carbon is taken as 4.
Question 24.
What is meant by hydrocarbon ? How are they classified?
Answer:
Hydrocarbons: These are those class of compounds in chemistry which contains only carbon and hydrogen as elements in their molecular formula and structure.
They are classified on the basis of number of covalent bonds between carbon carbon atoms as : -
a. Saturated hydrocarbon:
In this all the four valences if carbon are completed by covalent single bond with other atoms.
b. Unsaturated hydrocarbon:
In this the two carbon atoms are combined by double or triple bond.
Question 25.
Explain by drawing the shape of methane molecule.
Answer:
Methane is a saturated hydrocarbon and belongs to the alkane homologous series which is represented by the formula CnH2n+2.
All four of its valences are satisfied by single bonds with hydrogen atom giving a tetrahedral shape with the angle between any two bonds in methane molecule being 109o28’.
Question 26.
From which methane is obtained? Write its preparation.
Answer:
Methane is obtained from the marsh gas available from the mines of mineral coal and gas collected over petroleum in the sedimentary rocks in the crust of the earth. Methane I also present in dung, excretion of animals, gobar gas, sewage gas and biogas obtained from decomposition of plant and animal waste.
Methane gas is obtained by heating sodium acetate and soda lime.
CH3COONa + CaO + NaOH → CH4 + Na2CO3
Question 27.
Write uses of ethyne by writing its common name and structural formula.
Answer:
Common name : Acetylene
Structural formula :
Uses of ethyne
It is used for the preparation of ethanol, acetic acid, vinyl polymer and plastic like substances. It is used in oxyacetylene flame used for welding metals. It is filled in rubber gas balloons which are flown high in the sky.
Question 28.
What is isomerism? Write isomers of butane and pentane.
Answer:
Isomerism:
Organic compounds having the same molecular formula but different structural formula are called isomers and this phenomenon is called isomerism.
Butane isomers are :
Pentane isomers are :
Question 29.
The everyday life is not possible without mineral coal and petroleum. Why ?
Answer:
Almost everything that we use in our daily life ranging from cosmetics, wax , mould, plastics, synthetic fabrics ,lubricants, fuel in our kitchens as cooking gas, manufacture of synthetic rubber, dyes, solvents, pesticides, to running automobiles and drawing power is derived from mineral coal or petroleum. Hence without mineral coal and petroleum our life would come to a deadly stop.
Question 30.
Explain cracking reaction.
Answer:
Cracking reaction
In this big molecules break into smaller molecules.
Question 31.
Explain the destructive distillation of mineral coal in laboratory by drawing its figure.
Answer:
Destructive distillation of mineral coal in laboratory :
Mineral coal is taken in a hard glass test tube. In a second test tube some water is taken. The apparatus is arranged as shown in the figure:
The coal is heated in a Bunsen burner and the gas coming out is passed through water in the other test tube. Sometimes later deposition of coal tar would be found in the test tube containing water. A gas will come out through the tube connected with the upper part of the test tube. This gas is called coal gas. Now the portion left out in the tube containing mineral coal is called coke.
Question 32.
Write the types of mineral, coal, explain that the use of anthracite coal is more than the bitumen coal. Why?
Answer:
There are four main types of mineral coal. These are : -
a. Peat
Peat contains about 28% of Carbon. It is the primary state of transformation of coal from wood. It is known as rough coal. Wax, acetone, acetic acid, methanol, many cyclic organic compounds are obtained by fractional distillation of peat.
b. Lignite
It contains about 28 to 30% carbon along with volatile matter and moisture. The heat energy of lignite is 27kJg-1. It is used mostly in railways, thermal power and small and big industries. It is used to obtain coal gas and coal tar.
c. Bituminous coal.
It contains about 78 to 86% of carbon content. It also contains volatile matter and moisture. Its heat energy is about 30kJg-1. It is used as fuel in the production of steel and to generate electricity.
d. Anthracite
It is the highest quality of coal, containing 94 to 98% of carbon. It contains a small quantity of moisture and volatile matter. Its heat energy is 33kJg-1. When pure anthracite is burnt smoke and smell is not produced and the amount of residue is very less.
The use of anthracite coal is more than the bitumen coal because the carbon content in anthracite coal is more than the carbon content in the bitumen coal. Also when pure anthracite is burnt smoke and smell is not produced and the amount of residue is very less. Hence, it is very much environment-friendly and saves a lot of money that could have been used in the process of waste disposal.
Question 33.
Explain occurrence of methane and its preparation.
Answer:
Occurrence of methane
Methane is obtained from the marsh gas available from the mines of mineral coal and gas collected over petroleum in the sedimentary rocks in the crust of the earth. Methane I also present in dung, excretion of animals, gobar gas, sewage gas and biogas obtained from the decomposition of plant and animal waste.
Preparation of methane
Methane gas is obtained by heating sodium acetate and soda lime.
CH3COONa + CaO + NaOH → CH4 + Na2CO3
Question 34.
Writing the common molecular formulas of alkanes, and alkynes, write the names of first compound of each.
Answer:
The common molecular formula of : -
Alkane is – CnH2n+2
Alkyne is - CnH2n-2
The names of first compound of alkaneis – methane.
The names of first compound of alkyneis – ethyne.
Question 35.
Explain preparation of ethene in laboratory by drawing figure.
Answer:
Preparation of ethene in laboratory is as follows : -
At first take a hard glass test tube and in it put 3ml of melted wax and one tea spoon of sand. Then some porcelain is inserted in the front part of the test tube. The arrangement is made as shown in the following figure:
The test tube is then heated on a spirit lamp until the pieces of porcelain become red hot and then immediately heat the sand containing wax. Continue the heating process alternatively between the porcelain and the sand. When alkene vapours from wax pass through the heated porcelain ethane gas is liberated by cracking The gas is collected in a jar by downward displacement of water.
Question 36.
Explain preparation of ethyne in laboratory by drawing figure.
Answer:
Preparation of ethyne in laboratory is as follows : -
Take two to three small pieces of calcium carbide in a conical flask. The conical flask is arranged as shown in the figure below:-
Now as we add water through the thistle funnel, a chemical reaction takes place and ethyne is produced which could be collected in a jar by downward displacement of water.
Question 37.
What is meant by hydrocarbons ? Explain its classification in detail.
Answer:
Hydrocarbons: These are the category of compounds in chemistry which contains only carbon and hydrogen as elements in their molecular formula and structure.
These are classified on the basis of number of covalent bonds between carbon carbon atoms as: -
a. Saturated hydrocarbon:
In this all the four valences if carbon are completed by covalent single bond with other atoms.
b. Unsaturated hydrocarbon:
In this the two carbon atoms are combined by double or triple bond.
Question 38.
Explain in detail about natural gas.
Answer:
•Natural gas is collected over the petroleum in the rocks. The gas which is available with petroleum is called natural gas.
•It is obtained as an oily liquid along with petroleum or independently in the gaseous form. While drilling in the earth’s crust natural gas is obtained first followed by the petroleum.
•In natural gas the main hydrocarbon which is present is called methane . It also contains some other gaseous hydrocarbons like ethane, propane and butane with it.
•It is very easy to transport through gas pipelines and is widely used as a fuel in household uses in urban cities.
•It is also used as fuel to power thermal power plants to produce electricity.
Question 39.
What is meant by petroleum ? Explain in detail the refining of petroleum.
Answer:
Petroleum: Petroleum is defined as the mineral oil that has been originated from the fossils of plants and animal kingdoms buried under the surface of sea in prehistoric times.
Refining of petroleum:
•The impure oil which is available from the wells is transported to the refinery for purification by pipelines or by tankers. The natural gas is separated from it in the initial stage. The oil is allowed to settle in many large tanks in the refinery and the wastewater is separated.
•Then the fractional distillation of the oil is being carried out. In distillation, hydrocarbons are separated in fractions having specific useful properties for the industries. Each of these fractions is being distilled at a definite range of temperature, and it is a mixture of certain compounds. A typical distillation tower is as shown below: -
•
•Here petroleum is heated in a furnace and then sent to a fractionating column in the vapour form. The column is 2 to 4 meter in diameter and 30 to 60 meter high. Perforated shelves are fixed in it, and on each of these shelves, there is a cover like a cap.
•The substances which do not distill are collected at the lower part of the column. The vapour petroleum gets cooled while going up in the column and falls down in the form of liquid.
•The vapour passed through the liquid is collected on the shelves. Thus substances having higher boiling points come down in the form of the liquid and the substances having lower boiling point go up in the form of the vapour.
•In this way distillation continues near each shelf where compounds having nearby boiling points are separated.
•Here substances having a lower boiling point are collected in the shelves of the upper part while those having lower point are collected in the shelves of the lower part. The number and distance of the shelves are so arranged that a certain fraction is collected in the shelves at a certain height.