KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

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Students can Download Science Chapter 4 Carbon and Its Compounds Questions and Answers, Notes Pdf, KSEEB Solutions for Class 10 Science helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.

Karnataka State Syllabus Class 10 Science Chapter 4 Carbon and Its Compounds

KSEEB Class 10 Science Carbon and Its Compounds Intext Questions and Answers

Question 1.
What would be the electron dot structure of carbon dioxide which has the formula CO2?
Answer:
In carbon dioxide molecule, the two oxygen atoms are bonded on either side with carbon atom be double bonds. These there are 2 double bonds in CO2. Carbon shares its electrons in the formation of a double bond with one oxygen atom and another two electrons with another oxygen atom. In this process, both the oxygen atoms and the carbon atom acquire the stable electronic configuration of the noble gas neon. The formation of CO2 molecule is shown below.
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 1
Valencies of C and O are 4 and 2 respectively.

Question 2.
What would be the electron dot structure of a molecule of sulphur which is made up of atoms of sulphur? (Hint – The eight atoms of sulphur are joined together in the form of a ring.)
Answer:
The eight atoms of sulphur are joined – together is the form of a ring.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 2

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 3.
How many structural isomers can you draw for pentane?
Answer:
The five carbon atoms in pentane, C5H12 can be arranged in three different ways to give three structural isomers.
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 3

Question 4.
What are the two properties of carbon which lead to the huge number of carbon compounds we are seeing around us?
Answer:
(i) Catenation: Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules. This property is called catenation. These compounds may have long chains of carbon, branched chains of carbon or even carbon atoms arranged in rings. In addition, carbon atoms may be linked by single, double or triple bonds.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 4

(ii) Tetravalency: Since carbon has a valency of four, it is capable of bonding with four other atoms of carbon or atoms of some other monovalent elements. In order to satisfy its tetravalency, carbon can form double or triple bonds with other C-atoms or with oxygen, nitrogen also. Compounds of carbon are formed with oxygen, hydrogen, nitrogen, sulphur, chlorine and many other elements giving rise to compounds with specific properties which depend on the elements other than carbon present in the molecule.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 5.
What will be the structural formula and electron dot structure of cyclopentane?
Answer:
The molecular formula of cyclopentane is C2H10. Five carbon atoms of cyclopentane are connected by single bonds in a cyclic form. Following are the structural formula and electron dot structure of cyclopentane.
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 5

Question 6.
Draw the structures for the following Compounds.
Answer:
(a) Ethanoic acid
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 6
b) Bromopentane
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 7
c) Butanone
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 8
d) Hexanal
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 9

Question 7.
What are the names of the following compounds?
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 11

Question 8.
Why is the conversion of ethanol to ethanoic acid on oxidation process?
Answer:
The conversion of ethanol into ethanoic. acid is called an oxidation reaction because oxygen is added to it during this conversion.
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 12

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 9.
A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?
Answer:
If a mixture of oxygen and ethyne is burnt, then ethyne burns completely producing a blue flame. The oxygen ethyne flame is extremely hot and produces a very high temperature which is used for welding metals. A mixture of ethyne and air is not used for welding because burning of ethyne in air produces a sooty flame due to incomplete combination which is not enough to melt metals for welding.

Question 10.
What are oxidising agents?
Answer:
A substance which gives oxygen for oxidation is called an oxidising agent. Alkaline potassium permanganate and acidified potassium dichromate are strong o%idising agents.

Question 11.
How would you distinguish experimentally between an alehohol and a carborxylic acid?
Answer:
All the carboxylic acids decompose sodium hydrogen carbonate giving brisk effervescence of carbon dioxide gas whereas ethanol does not react with sodium hydrogen carbonate

Experiment:

  1. Take two test tubes, label them as A and B
  2. Take about 0.5 g of sodium hydrogen carbonate (NaHco3) in each test tube
  3. Add 2 ml of ethanol in test tube A and 2ml of ethanoic acid in test tube B.
  4. We can observe the gas bubbles in test tube B. No such bubbles are seen in test tube A. Pass the gas produced in test tube B through lime water taken in another test tube
  5. We will find that lime water turns milky It is a test for carbon dioxide.

Hence, this experiment proves that when ethanoic acid reacts with sodium hydrogen carbonate, then carbon dioxide gas is produced with an effervescence (a rapid evolution of gas bubbles). Ethanol does not react with NaHCo3.

Question 12.
Would you be able to check ¡f water is hard by using a detergent?
Answer:
No, we would not be able to check whether a sample of water is hard by using detergent because a detergent forms lather easily even in hard water.

Question 13.
People use a variety of methods to wash clothes usually after adding the soap, they beat the clothes on a stone1 or beat it with a paddle scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?
Answer:
Agitation is necessary to get clean clothes because the soap micelles which entrap oily or greasy particles on the surface of dirty cloth have to be removed from its surface when the wetted cloth in soap solution is agitated, the micelles containing oily or greasy dirt particles get removed from the surface of dirty cloth and go into the water and the dirty cloth gets cleaned.

KSEEB Class 10 Carbon and Its Compounds Textbook Exercise Questions and Answers

Question 1.
Ethane, with    the   molecular formula C2H6 has
(a) 6 covalent bonds
(b) 7 covalent bonds
(c) 8 covalent bonds
(d) 9 covalent bonds.
Answer:
(b) 7 covalent bonds

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 2.
Butanone is a four-carbon compound with the functional group
(a) Carboxylic acid
(b) Aldehyde.
(c) Ketone
(d) Alcohol.
Answer:
(c) Ketone

Question 3.
While cooking, if the bottom of the vessel is getting blackened on the outside, it means that
(a) The food is not cooked completely.
(b) The fuel is not burning completely.
(c) The fuel is wet.
(d) The fuel is burning completely.
Answer:
(b) The fuel is not burning completely

Question 4.
Explain the nature of the covalent bond using the bond formation in CH3
Answer:
Covalent bond is formed by sharing of electrons so that the combining atom complete their outer most shell. In CH3Cl, this happens as follows.
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 13

Three hydrogen atoms complete their shells by sharing three electrons of carbon atom. Chlorine completes its outer shell (L = 7 + 1 = 8) by sharing its one out of seven electrons with one electron of a carbon atom. Thus carbon atom shares in all its four electrons with three of three hydrogen atoms and one of chlorine atom and completes its outer shell (L = 4 + 3 + 1 = 0).

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 5.
Draw the electron dot structures for
(a) ethanoic acid
(b) H2
(c) propanone.
(d) F2
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 14
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 15

Question 6.
What is a homologous series? Explain with an example.
Answer:
A homologous series is a group of compounds that contains the same functional group but different chain lengths. Thus these have the same chemical properties but different physical properties.
Ex:  CH3OH, C2H5OH, C3H7OH,
C4H9OH are members of the same homologous series.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 7.
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
Answer:

Test Ethanol Ethanoic acid
litmus test No change in colour of litmus solution. Blue litmus solution turns red.
Sodium
Carbonate
No brisk effervescence. Brisk effervescence due to evolution of
Sodium metal test H2 is given  out with  effervesence. H2 is  produced but no effervesence.

Question 8.
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Answer:
The molecules of soap are sodium or potassium salts of long-chain carboxylic acids. The acid end of soap dissolves in water while the carbon chain dissolves in oil when soap is added to water, the hydrophilic (acid end) end will align along the surface of water and the hydrophobic tail (carbon chain) remains out of water. This cluster of molecules in which hydrophobic tails are in the interior of cluster and the ionic ends are on the surface of cluster is called micelle. Such micelle formation will not be possible in other solvents like ethanol in which sodium salt of fatty acids do not dissolve.

Question 9.
Why are carbon and its compounds used as fuels for most applications?
Answer:
Carbon and its compounds give a large amount of heat per unit weight and are therefore used as fuels for most purposes.

Question 10.
Explain the formation of scum when hard water is treated with soap.
Answer:
Hard water contains salts of calcium and magnesium. Calcium and magnesium on reaction with soap (carboxylic acid) forms insoluble substance called scum.

Question 11.
What change will you observe if you test soap with litmus paper (red and blue)?
Answer:
Red litmus will turn blue because soap is alkaline.

Question 12.
What Is hydrogenation? What is its industrial application?
Answer:
The addition of hydrogen to unsaturated, hydrocarbon in the presence of catalyst is called hydrogenation. Industrial application: Vegetables oils have long unsaturated carbon chains.These on hydrogenation in the presence of nickel catalyst form saturated carbon chains which are animal fats or ghee. Thus ghee on industrial scale is made By hydrogenation of naturally available vegetable oils.

Question 13.
Which of the following hydrocarbons undergo addition reactions:
C2H6, C3H8, C3H6, C2H2 and CH4.
Answer:
C3H6 and C2H2

Question 14.
Give a test that can be used to differentiate chemically between butter and cooking oil.
Answer:
Cooking oil is unsaturated hydrocarbon whereas butter is saturated hydrocarbon. We know that brown colour of bromine disappears when a drop of bromine is added to an unsaturated compound whereas there is no reaction between saturated hydrocarbons and bromine. Thus when a drop of bromine is added to cooking oil, its colour disappears whereas when a drop of bromine is added to butter, it becomes brown.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 15.
Explain the mechanism of the cleaning action of soaps.
Answer:
Soaps form micelles in water. The oily dirt from clothes get attached to the centre of micelle. The micelles do not come close,   to each other and get separated due to ion repulsion. The micelles containing oil dirt thus stay in solution as colloid and are easily rinsed away.

Fill in the blanks:

Question 1.
The next higher homologue of ethyne is______
Answer:
Propyne

Question 2.
Isomerism is more is possible only with hydrocarbons having ______ or more carbon atoms.
Answer:
4

Question 3.
The organic compounds having the same molecular formula but different structures are known as.
Answer:
Isomers

Question 4.
Hydrocarbons having the general formula CnH2n+2 are called _____
Answer:
Alkanes

Question 5.
C2H2n  is the general form of _____
Answer:
Alkenes

Question 6.
Alkanes with one to four carbon at per molecule are _____ at room temperature
Answer:
Gases

Question 7.
The process of burning of a hydrocarbon in presence of excess air to give CO2H2O with the evolution of heat and light is known as _____
Answer:
Combustion

Question 8.
The reactive part of the organic molecule is called its_____ group.
Answer:
Functional

Question 9.
Ethanol can be prepared by the fermentation of _____
Answer:
Cane sugar

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 10.
The presence of Caz+ and Mgz+ ions is water makes _____ ineffective for washing clothes.
Answer:
Soaps

Question 11.
Sodium lauryl sulphate is an example of _____
Answer:
Synthetic detergent

Question 12.
Soaps are the alkali salts of _____
Answer:
Higher fatty acids

Multiple choice questions:

Question 1.
Which of the following compounds is not a hydrocarbon?
a) R – CH3
b) RCH = CH2
c) RCH2OH
d) CH3CH = CH2
Answer:
c) RCH2OH

Question 2.
Select an alkene from the following
a) C5H10
b) C4H10
c) C6H10
d) C6H8.
Answer:
a) C5H10

Question 3.
Which of the following pairs are not isomers?
a) n-butane & isobutane
b) n – pentane & neopentane
c) 1 – butyne & 2 – butyne
d) Propane and methyl propane.
Answer:
d) Propane and methyl propane.

Question 4.
Select a sweet-smelling compound out of the following
a) CH3 CH2 CH2OH
b) CH3CH2X
c) CH3CH2COOH
d) CH3 COOC2H5
Answer:
d) CH3 COOC2H5

Question 5.
Which of the follow ing is not a pair of the same homologous series?
a) CH3CH2OH, CH3CH2Cl
b) CH3CH3,CH4
c) CH3CH2COOH, CH3COOH
d) C2H4, C3H6
Answer:
a) CH3CH2OH, CH3CH2Cl

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 6.
Which of the following would give substitution products with chlorine?
a) CH3CH3
b)CH2 = CH2
c) CH = CH
d) CH3C = CH
Answer:
a) CH3CH3

Multiple choice questions:

Question 1.
The simplest Hydrocarbon
a) Butane
b) Propane
c) Ethane
d) Methane
Answer:
d) Methane

Question 2.
The molecular formula of an alkene containing 2 carbon atom is
a) Ethene
b) Propene
c) Butene
d) Pentene
Answer:
a) Ethene

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 3.
Butane has
a) 8 covalent bonds
b) 10 covalent bonds
c) 12 covalent bonds
d) 14 covalent bonds
Answer:
b) 10 covalent bonds

Question 4.
Ethanol reacts with sodium to form two products. These are
a) Sodium ethanoate and hydrogen
b) Sodium ethanoate and oxygen
c) Sodium ethanoate and carbon
d) Sodium ethoxide and hydrogen
Answer:
d) Sodium ethoxide and hydrogen

Question 5.
Valency of carbon is
a) 2
b) 4
c) 6
d) 8
Answer:
b) 4

Question 6.
Chemistry of carbon is known as
a) Organic chemistry
b) Inorganic chemistry
c) Bio chemistry
d) Petro chemistry
Answer:
a) Organic chemistry

Question 7.
General formula of Alkene
a) CnH2n+2
b) CnH2n
c) CnH2n2
d) CnH2n 6
Answer:
b) CnH2n

Question 8.
General formula of Aldehyde
a) COOH
b) OH
c) CHO
d) NH2
Answer:
c) CHO

Question 9.
Since a carbon atom has four electrons in its outer most orbit it is
a) Tetravalnet
b) Pentavalent
c) Trivalent
d) None of these
Answer:
a) Tetravalnet

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 10.
The vital force theory was put for word by
a) Daltan
b) Thomson
c) Berzelius
d) Wholer
Answer:
c) Berzelius

KSEEB Class 10 Science Carbon and Its Compounds Additional Questions and Answers

Question 1.
State any 3 physical properties of carbon compounds.
Answer:

  • These have low melting points and boiling points.
  • These don’t conduct electricity either in the solid-state or in molten state or in the solution form. They are non – electrolytes.
  • These are readily soluble is non­polar solvents like benzene, carbon tetrachloride, etc but do not dissolve in polar solvents like water.
  • The covalent bond is directional in nature.

Question 2.
Name the process by which unsaturated fate are changed to saturated fats?
Answer:
Hydrogenation

Question 3.
Why are unsaturated hydrocarbons more reactive than saturated hydrocarbons?
Answer:
Unsaturated hydrocarbons are more reactive due to the presence of C = C. C ≡ C bonds which are weaker than, the single bond in saturated hydrocarbons. These double and triple bonds are the reactive sites in the unsaturated hydrocarbons which easily give additional reactions.

Question 4.
Give reasons for the following observations
a) air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame.
Answer:
We need to adjust air holes of gas furnace so that sufficient oxygen-rich mixture is burnt to give a clean blue flame for complete combustion.

b) Use of synthetic detergents causes pollution of water.
Answer:
Synthetic detergents are generally non-bio degradable, that is they are not decomposed by microorganisms like bacteria Hence, use of synthetic detergents causes water pollution.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 5.
An element of group 14 has two common allotropes. A and B. A is very hard and is bad conductor of electricity white B is soft to touch and good conductor of electricity Identify the element and ts allotropes. Explain reasons for different properties.
Answer:
The element is carbon and two allotropes are diamond and graphite Diamond has 3D rigid hence it is hard and bad conductor of electricity. Hence it is hard and bad conductor of electricity. Graphite forms hexagonal sheet-like structure and one valency with carbon is free. Hence graphite is soft and a good conductor of electricity.

Question 6.
Why are detergents better than soaps in cleaning?
Answer:
Detergents work as cleansing agent in hard and soft water both because the charged ends of detergents do not form insoluble precipitates with calcium and magnesium ions in hard water.

Question 7.
Why are soaps not suitable for washing clothes with hard water?
Answer:
Soaps are not suitable for washing clothes with hard water because

  • Soap reacts with the calcium and magnesium ions present in hard water to form insoluble precipitate called scum. This results in the wastage of soap.
  • The sticky scum sticks to the clothes being washed and interferes with the cleaning ability of soap. This makes the cleaning of clothes difficult.

Question 8.
Structural formula and electron dot structure of the following:

  1. Proponoic acid
  2. Benzene
  3. Pentanal
  4. Pentanone

Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 16
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 17
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 18
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 19

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 9.
The general formula of the following :

  1. Alkanes
  2. Alkenes
  3. Alkynes
  4. Alcohol
  5. Aldehydes
  6. Carboxylic acid
  7. Amines
  8. Ketones

Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 28

Question 10.
Match the following:

A B
CnH2n + 2 a) Benzene
CnH2n – 2 b) Aldehyda
CnH2n c) Alkane
C6H6 d) Napthalena
e) Alkene
 f) Alkyne

Answer:

  1. (c) Alkane
  2. (f) Alkyne
  3. (e) Alkene
  4. (a) Benzene

Question 11.
Match the following:
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 20

Question 12.
Write four chemical reactions that show how methane loses hydrogen atoms in substitution reaction with chlorine.
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 21
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 22

Question 13.
What are oxidising agent?
Answer:
Oxidising agents are those compounds – which can supply oxygen or can remove hydrogen.
Ex: Alkaline KMnO4 is an oxidising agent

Question 14.
What are the differences between saturated and unsaturated hydrocarbon.
Answer:
Saturated Hydrocarbon

  • Only single bond is present between carbon-carbon atom.
  • Less reactive
  • It burns with blue flame.
  • Substitution reaction occurs. Unsaturated hydrocarbon
  • Double or triple bond is present in between carbon-carbon atoms.
  • It burns with yellow flame.
  • Highly reactive.
  • Addition reaction occurs.

Question 15.
Why does carbon form compounds by covalent bonding.
Answer:
Carbon has four electrons in the outer most shell to attain octet it has to lose or gain four electrons it cannot lose four electrons as very high energy is needed it cannot gain four electrons easily because of repulsion. As it can share four electrons easily carbon forms covalent bonds.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 16.
Why are soaps ineffective in hard water?
Answer:
Hard water contains Mg2+ and Ca2+ ions which reacts with soap to form insoluble calcium salts of fatty acids. Therefore soaps become ineffective.

Question 17.
Write the structural formula of the following:
a) Methanol
b) Ethanol
c) Proponol
d) Butanol
Answer:
a) Methanol
b) Ethanol
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 23
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 24

Question 18.
Write the structural formula of the following:
a) Ethanal
b) Proponal
c) Butanal
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 25

Question 19.
Write the structural formula of the following:
a) Ethanoic acid
b) Proponoic acid
c) Butanoic acid
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 26

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 20.
Write the structural formula of the following:
a) Ethanamine
b) Propaamine
Answer:
KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds 27

Question 21.
What are the properties of Carbon
Answer:

  • Catenations
  • Tetravalency
  • Isomerism

Question 22.
What are the properties of Ethanol and Ethanoic acid.
Answer:
Ethanol

  • It’s commonly called alcohol
  • It is good solvent
  • Is is soluble in water
  • It is used in medicines

Ethanoic acid

  • It is commonly called acetic acid
  • It is called Vinegar
  • The group called Carboxalic acid
  • It is used for preservative in pickles

Question 23.
What are the difference between Soaps and Detergents.
Answer:

Soap Detergents
1. It is made from fat and vegetable oil 1. It is made from petroleum
2. It clean well in soft water 2. It clean well both in soft and hard water
3. It do not clean well in acidic medium 3. It clean well even in acidic medium

Question 24.
Characteristic of Homologous series
Answer:

  • Have same general formula
  • Have similar chemical properties
  • They belong to the same functional group
  • Have general methods of separations.

KSEEB Solutions for Class 10 Science Chapter 4 Carbon and Its Compounds

Question 25.
What are the physical properties of Methane.
Answer:

  • It is colourless
  • It is odourless gas
  • It is lighter than air.
  • It is slightly soluble in water.14

Question 26.
What are the difference between complete and incomplete combustion?
Answer:
Complete Combustion
Methane burns with air with a blue flame forming carbon dioxide and water.
CH4 + 2O2 → CO2 + 2H2O

Incomplete Combustions
Methane gas burns with a yellow flame forming carbon monoxide and water.
2CH4 + 3O2 →  2CO + 4H2O

Question 27.
How are fat different from oil.
Answer:
fat

  • fats are saturated and solid at room temperature
  • fat digest slowly
  • fat chemically less reactive

Oil

  • oils are mostly unsaturated and liquid at room temperature.
  • oils are easy to digest
  • oils are chemically reactive

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