CBSE Class 10 Chemistry Carbon and Its Compounds Worksheet Set D

Important Terms & Conditions:

Versatility of carbon: Carbon is a non metal and occurs in free as well combined state in nature.

Free State: Diamond, graphite and coal.

Combined state: 1. Solid State-All animals and plants products.

                           2. Liquid state-Petroleum and vegetable oils.

                           3. Gaseous state: In air as CO₃.

Carbon has 4 valance electrons carbon can form an anion C-4 by gain of electrons. It can also form cations C+4 by loss of electron.IT can share its balanced electrons with other carbon atoms or atoms of non metals and forms covalent bonding.

Compounds of carbon: Simplest compound of carbon are hydrocarbons, and simplest hydro carbon is methane.

Classification of hydro carbon:

Isomerism: The phenomenon of existence of compounds in two or more forms with same molecular formula but different structure.

Functional group: An atom or groups of atoms which makes a carbon compound reactive and decide its properties.

HOMOLOGOUS SERIES: A series of compounds in which the same functional group substitute for hydrogen in a carbon chain, such that successive compounds differ by CH₂ group,e.g.,CH₄, C₂H₆, C₃H₈, etc.

NOMENCLATURE OF CARBON COMPOUNDS:

Prefix + word root + Suffix + Functional group.

CARBON COMPOUNDS:

1. ETHANOL-C₂H₅OH, common name ethyl alcohol

2. ETHANOIC ACID-CH₃COOH , Common name acetic acid.

3. ESTERIFICATION REACTION: The reaction between carboxylic acid and an alcohol in the presence of conc. Sulphuric acid to form a sweet smelling substance ester is called esterification. e.g.,

                                 Conc. H₂SO₄

CH₃COOH+C₂H₅OH -------------------- CH₃COOC₂H₅ + H₂O

4. SPONIFICATION REACTION: Alkaline hydrolysis of ester produces soaps.

                                            Heat

CH₃COOC₂H₅ + NaOH ------------------------ CH₃COONa + C₂ H₅OH

5. Reaction with carbonates and hydrogen carbonates: reaction of ethanoic acid with carbonates or bi carbonates evolves carbon di oxide gas.

2CH₃COOH + Na₂Co₃ 2CH₃COONa + CO₂ + H₂O

SOAPS AND DETERGENTS. Soap is sodium and potassium salt of long chains of carboxylic acids. They foam lather with soft water only.

Detergent are ammonium or sulphonate salts of long chain of carboxylic acids. They even remain effective in hard water and foam lather.

Question. The IUPAC name of (CH₃)₂CHCH₃ is -
(A) 2-Methylpropane
(B) 2,2-Dimethylethane
(C) Trimethylmethane
(D) none of these
Answer : A

Question. The IUPAC name of the following compound is - CH₂ = CH – CH(CH₃)₂
(A) 1,1-Dimethyl-2-propene
(B) 3-Methyl-1-butene
(C) 2-Vinyl propane
(D) 1-Isopropyl ethylene
Answer : B

Question. In a double covalent bond number of electron pairs shared are -
(A) 2
(B) 3
(C) 4
(D) 6
Answer : A

Question. Which of the following compound contain single covalent bond ?
(A) Oxygen
(B) Nitrogen
(C) Methane
(D) Carbon dioxide
Answer : C

Question. Carbon dioxide molecule contains -
(A) single covalent bond
(B) double covalent bond
(C) triple covalent bond
(D) ionic bond
Answer : B

Question. Covalent compounds can be dissolved in -
(A) benzene
(B) ether
(C) alcohol
(D) all of these
Answer : D

Question. Covalent compounds are generally-
(A) good conductors of electricity.
(B) bad conductors of electricity.
(C) semiconductors of electricity.
(D) none of these
Answer : B

Question. Which of the following allotropic form of Carbon used in making Crucibles -
(A) Diamond
(B) Graphite
(C) Fullerene
(D) Coke
Answer : B

Question. Diamond means :
(A) Transparent
(B) Hardness
(C) Both A and B
(D) Conductor
Answer : C

Question. Bond length between carbon-carbon atoms in diamond is :
(A) 1.34 A°
(B) 1.40 A°
(C) 1.54 A°
(D) 1.7 A°
Answer : C

Question. Graphite is used in making electrodes because :
(A) It has high melting point
(B) It is soft and slippery
(C) It is a good conductor of electricity
(D) None of these
Answer : C

Question. Graphite melts at a high temperature of about :
(A) 4236°C
(B) 5326°C
(C) 3730°C
(D) 6326°C
Answer : C

Question. The general formula for saturated hydrocarbons is -
(A) C_nH_2n+2
(B) C_nH_2n
(C) C_nH_2n–2
(D) C_nH_2n–n
Answer : A

Question. Select the alkyne from the following -
(A) C₄H₈
(B) C₅H₈
(C) C₇H₁₉
(D) None of these
Answer : B

Question. In order to form branching, a saturated organic compound must have a minimum of -
(A) four carbon atoms
(B) three carbon atoms
(C) five carbon atoms
(D) any number of carbon atoms
Answer : A

Question. The number of C – H bonds in ethane (C2H6) molecule is -
(A) four
(B) six
(C) eight
(D) ten
Answer : B

Question. Which of the following does not belong to alkane ?
(A) C₂H₄
(B) CH₄
(C) C₂H₆
(D) C₄H₁₀
Answer : A

Question. The IUPAC name of (CH₃)₂CHCH₂ CH₂ Br is
(A) 1-Bromopentane
(B) 2-Methyl-4-bromo pentane
(C) 1-Bromo -3- methyl butane
(D) 2-Methyl-3-bromo pentane
Answer : C

Question. IUPAC name of CH₃CH₂OH is -
(A) wood spirit
(B) methyl carbinol
(C) ethanol
(D) ethyl alcohol
Answer : C

Question. The IUPAC name of the compound having the formula (CH₃)₃CCH = CH₂ is -
(A) 3,3,3-Trimethyl-1-propene
(B) 1,1,1-Trimethyl-1-propene
(C) 3,3-Dimethyl-1-butene
(D) 1,1–Dimethyl-2-butene
Answer : C

Question. Sometimes during cooking the bottom of the vessel becomes black from outside. This means that -
(A) food is not cooked properly.
(B) fuel is not burning completely.
(C) fuel is burning completely.
(D) fuel is dry.
Answer : B

Question. Rectified spirit is -
(A) 50% ethanol
(B) 80% ethanol
(C) 95% ethanol
(D) 100% ethanol
Answer : C

Question. Glacial acetic acid is -
(A) 100% acetic acid free of water.
(B) solidified acetic acid.
(C) gaseous acetic acid.
(D) frozen acetic acid.
Answer : A

Question. Which of the following will react with sodium metal ?
(A) Ethanol
(B) Ethanal
(C) Ethene
(D) Ethane
Answer : A

Question. Power alcohol contains -
(A) 50% petrol and 50% ethanol
(B) 80 % petrol and 20% ethanol
(C) 25 % petrol and 75% ethanol
(D) 70 % petrol and 30% ethanol
Answer : B

Question. A by product of soap industry is -
(A) sodium hydroxide
(B) sodium palmitate
(C) glycerol
(D) Both B & C
Answer : C

Question. Which one of the following statements is incorrect about soaps ?
(A) Soaps are biodegradable.
(B) Soaps are sodium salts of higher fatty acids.
(C) Soaps are prepared from natural oils & fats.
(D) Soaps can be used in acidic solutions.
Answer : D

Question. Which of the following is not correctly matched ?
(A) Hard soaps - sodium salts of fatty acids.
(B) Soft soaps - potassium salts of fatty acids.
(C) Hydrophilic - water insoluble
(D) None of these
Answer : C

Question. Cleansing action of soaps includes :
(A) formation of micelles .
(B) emulsification of oil or grease.
(C) lowering of surface tension of water.
(D) all of the above.
Answer : D

Question. Washing powders contain detergent in the following range -
(A) 10 – 15%
(B) 15–30%
(C) 50 – 60%
(D) 40 – 50%
Answer : B

Question. What would be the product when a compound containing carbon is burnt?
Answer. CO₂

Question. What is the amount of carbon present in the earth's crust?
Answer. 0.02%

Question. What is the distribution of electrons in various shells of carbon?
Answer. 2+4

Question. Writethe number of covalent bonds in the molecule of ethane.
Answer. 7

Question. Covalent compounds are generally poor conductors of electricity. Why?
Answer. The electrons in covalent compounds are shared between atoms to form covalent compounds. They do not form any charged particles . Therefore, covalent compounds are poor conductor of electricity.
Evaluation based

Question. Write the name and structure of an aldehyde with four carbon atoms in its molecule.
Answer. Butanal (draw structure)

Question. Write the name and molecular formula of the first members of the homologous series of alkynes.
Answer. Ethyne (C₂H₂), Propyne (C₃H₄), Butyne [1-Butyne and 2-Butyne] (C₄H₆).

Question. Priyanka went to Mussoorie with her parents. While washing her hands and face with soap, she noticed that scum was formed on her hands in place of lather. Why does this happen?
Answer. hard water. When soap is mixed with hard water it forms scum insted of lather.

Question. Adi's sister studies in class X and told him that the pencil is made up of carbon. He did not believe and asked his teacher. Which form of carbon is used to make lead of pencil and why?
Answer. lead of pencil is made of graphite. Graphite is an allotrope of carbon.

Question. We know that water is a universal solvent. When we try to dissolve ester in the water, it does not dissolve.
Why does ester not dissolving water?
Answer. Water is a ionic solvent which can dissolve polar substances which easily split into ions. Ether is an organic and non polar substance.

Question. Why are carbon and its compounds used as fuels for most applications?
Answer. Carbon compounds are used as fuel because they burn with a clean flame and no smoke is produced.
Carbon compounds have higher calorific values, maximum ignition temperature and their combustion can be restrained. Hence, carbon and its compounds are a great source of fuel.

Question. What would be the electron dot structure of a molecule of sulphur which is made up of 8 atoms of sulphur?
Answer. The eight atoms of Sulphur are joined together in the form of a ring).

Question. What happens when 5% of alkaline potassium permanganate solution is added drop by drop to warm propyl alcohol taken from a test tube? Explain with the help of a chemical equation.
Answer. purple colour of potassium permanganate gradually disappears as it oxidizes the propanol to its respective carboxylic acid i.e propionic acid. Write chemical reaction)

Question. Why is the conversion of ethanol to ethanoic acid and oxidation reaction?
Answer. A molecule of ethanol contains six hydrogen atoms while that of ethanoic acid contains four hydrogen atoms since oxidation involves removal of hydrogen, therefore conversion of ethanol to ethanoic acid is an oxidation reaction.

Question. Write the structural formula of any four isomers of hexane.
Answer. Write structural formula of C6H₁₂

Question. Write the functional groups present in the following compounds:
CH₃ COCH₂ CH₂ CH₂ CH3
Answer.keton

CH₂ CH₂ CH₂ COOHAnswer.
Carboxylic acid

CH₃ CH₂ CH₂ CH₂ CHO
Answer.Aldehyde

CH₃ CH₂ OH
Answer.Alcohal

Question. A gas is evolved when ethanol reacts with sodium. Name the gas evolved and also write the balanced chemical equation of the reaction involved.
Answer. When ethanol reacts with sodium, then hydrogen gas is evolved. This reaction can be given
by following equation: 2Na+2CH₃CH₂OH→2CH₃CH₂ONa+H₂.

Question. For elements given below with their electronic configuration:
P (2,6); Q (2,8,1); R (2,8,7); and S (2,8,8).
Identify which element(s) will form covalent bonds with carbon.
Answer. P and R

Question. "Carbon Reacts with an element in the above table to form several compounds." Give a suitable reason.
Answer. Carbon has tetravalency and catenation

Question. What is a micelle? Draw the structure of the missile that would be formed if we dissolve soap in a hydrocarbon.
Answer. The molecule of soap constitutes sodium or potassium salts of long-chain carboxylic acids. In the case of soaps, the carbon chain dissolves in oil and the ionic end dissolves in water. Thus, the soap molecules form structures called micelles. In micelles, one end is towards the oil droplet and the other end which is the ionic faces outside.) (draw the structure of micelle

Question. How would you distinguish experimentally between an alcohol and a carboxylic acid?
Answer. Carboxylic acid and Alcohol can be distinguished by using Sodium bicarbonate as, Carboxylic acid produces a brisk effervesce when reacted with it, whereas Alcohols do not produce anything when reacted with Sodium bicarbonate.

Question. The general formula of the organic compounds 'P', 'Q' and 'R' is C_nH_2n. There boiling points are -162 °C,-42.2 °C and -0.5 °C respectively. Based on this information answer the following:
Which type of compounds 'P', 'Q' and 'R' are and why?
Answer. P. Q and R are alkenes because their general formula is C_nH_2n

Question. Which of these has maximum number of carbon atoms in the molecule and why?
Answer. Compound R has maximum number of carbon atoms because boiling point increase with molecular mass which depends on number of C atoms)

Question. Write the name and structural formula of the second member of this series.
Answer. Name: propane Structural formula: CH₃-CH=CH₂

Question. Write the name and molecular formula of an organic compound having its name suffixed with 'ol' and having two carbon atoms in its molecule. Write a balanced chemical equation to indicate what happens when this compound is heated with excess conc. H₂SO₄ and the name of the main product formed. Also state the role of conc. H₂SO₄ in the reaction.
Answer. Alcohols have 'ol' suffix. Ethanol (CH₃CH₂OH) is alcohol with 2 carbon.
When ethanol is heated with excess concentrated sulphuric acid at 443 K, dehydration takes place and ethene is formed. In this reaction concentrated sulphuric acid acts as a dehydrating agent.

PUZZLE:. COLLECT THE LETTERS FROM THE TABLE AND MAKE

APPROPRIATE WORDS USING FOLLOWING CLUES:

The answers have been provided in the puzzle you can look for the answer horizontally, (left to right), vertically (upwards and downwards) or diagonally.

1. Compounds containing double and triple bonds.

2. A compound which is basic constituent of many cough syrups.

3. Very dilute solution of ethanoic acid.

4. A sweet smelling substance formed by the reaction of alcohol and carboxylic acids.

5. Gas released when sodium metal is dropped in ethanol.

6. The functional group present in methanol.

7. IUPAC name of alkene containing 3 carbon atoms.

8. The number of single covalent compounds present in pentane.

9. First member of homologous series alkyne.

10. Simplest ketone.

11. Self linking property of carbon.

12. Product formed by dehydration of ethanol in conc. Sulphuric acid.

13. Alcohol whose intake in small quantities can be lethal.

14. Number of single covalent bonds in ammonia.

15. Type of reactions shown by alkanes.

ACTIVITY:

To study the saponification reaction reaction for the preparation of soap in the laboratory using any vegetable oils.

Prepare soaps of different colours and fragrances.

PROJECTS:

To prepare models of methane, ethane, ethyne and benzene molecules using thermocols, ball and match sticks.

TOPICS FOR DEBATE:

1. Role of esters in everyday life.

2. Condemning the use of alcohol as a social practice.

3. Use of biodegradable synthetic detergents for cleansing purpose.

HIGH ORDER THINKING SKILLS (HOTS) QUESTIONS:

1. Why the colour of potassium permanganate disappears if it is added to warm solution of ethanol?

2. An organic compound with molecular formula C₂H₄O₂ produces brisk effervescence on addition of sodium carbonate /bicarbonate.

(a). Identify the organic compound.

(b) Name the gas evolved.

(c) How will you test the gas evolved?

(d) Write the chemical equation for the above reaction.

(e) List two important uses of the above compound.

3. (a) what are the various possible structural formulae of a compound having molecular formula C₃H₆O?

(b). Also, give the IUPAC names of the above possible compounds.

(c) . What is the similarity in these compounds?

4. A mixture of oxygen and ethyne is burnt for welding. Can you tell why a mixture of ethyne and air is not used?

5. Two carbon compound A and B have molecular formula C₃H₈ and C₃H₆ respectively. Which one of the two is most likely to show addition? Justify your answer. Explain with the help of a chemical equation, how an addition reaction is vegetable ghee industry.

6. 1 ml glacial acetic acid and 1ml of ethanol are mixed together in a test tube. Few drops of concentrated sulphuric acid is added in the mixture are warmed in a water –bath 5 minutes.

(a) Name the resultant compound formed.

(b) Represent the above change by a chemical equation.

(c) What term is given to such reaction?

(d) What are the special characteristics of the compound formed?

7. An organic compound 'X' with a molecular C₂H₆O undergoes oxidation in the presence of alkaline KMnO₄ and forms the compound 'Y'

(a) Identify 'X' and 'Y'

(b) Write your observation the compound 'X' is made to react with compound 'Y' which is used as a preservative for pickles.

HOTS Questions

Question. A, B, C are members of homologous series their melting points are –183°C, –138°C, 130°C respectively. Among these
(i) Which member will have least number of carbon atoms?
(ii) Which member will have maximum number of carbon atoms?
Answer : (i) A will have least number of carbon atoms.
(ii) C will have maximum number of carbon atoms.

Question. Write an activity to show the acidic nature of ethanol. Give the chemical equation of the reaction taking place.
Answer : Take ethanol in a test tube and drop a small piece of sodium about the size of a grain of rice into it. The reaction evolves a colourless gas which is hydrogen.
Hydrogen gas can be tested by bringing a burning splinter/match stick near the mouth of the test tube, it burns with the popping sound.
This activity proves that ethanol like other acids release H₂ gas
2Na + 2CH₃CH₂OH ⎯⎯→ 2CH₃CH₂ONa + H₂

Value Based Questions

Question. A student reports the police about the illegal vending of alcohol near his school. He also knew about denatured alcohol.
(a) What is denatured alcohol?
(b) What would happen if somebody consumes denatured alcohol?
(c) What value is reflected by a student who reported the matter to police?
Answer. (a) Denatured alcohol is ethanol when added with poisonous methanol or copper sulphate solution.
(b) On drinking denatured alcohol a person may die.
(c) Value reflected by student is society’s law and order.

Question. Geeta helps her mother in washing clothes, toilets, balconies every Sunday. She uses the leftover detergent water of washing machine to clean toilets.
(a) Why is detergent used in washing clothes?
(b) Give one advantage of detergent over soap.
(c) What value of Geeta is reflected in the above task?
Answer : (a) Detergents have strong cleansing ability and can remove oil and dirt from clothes or other surfaces.
(b) Soap cannot be used in hard water but detergents can be used in hard water.
(c) Geeta is trying to reduce water pollution and water shortage problem. She also shows helpful to her mother and responsible behaviour.

 

OBJECTIVE TYPE QUESTIONS

Question. Which of the following is not the use of graphite?
(a) It is used as lubricant
(b) It is used in manufacturing of lead-pencils
(c) It is used in manufacturing of artificial diamond
(d) It is used for making insulated plates
Answer. (d) It is used for making insulated plates
Graphite cannot be used for making insulated plates, as it is a good conductor of electricity.

Question. Methane, ethane and propane are said to form a homologous series because all are-
(a) Hydrocarbons
(b) saturated compounds
(c) aliphatic compounds
(d) differ from each other by a CH₂ group
Answer. (d) differ from each other by a CH₂ group

Question. Why does carbon form compounds mainly by covalent bonding?
(a) There are four electrons in the outermost shell of carbon.
(b) It requires large amount of energy to form C⁴⁺ or C^4-
(c) It shares its valence electrons to complete its octet.
(d) All the above.
Answer. (d) All the above

Question. Which of the following belongs to homologous series of alkynes?
C₆H₆, C₂H₆, C₂H₄, C₃H₄
(a) C₆H₆
(b) C₂H4
(C) C₂H₆
(d) C₃H₄
Answer. C₃H₄

Question. In diamond, each carbon atom is bonded to four other carbon atoms to form
(a) a hexagonal array
(b) a rigid three-dimensional tetrahedral structure
(c) a structure in the shape of a football
(d) a structure of a ring
Answer. (b) a rigid three-dimensional tetrahedral structure.

Question.

(a) 2-ethyl-2-methyl propane
(b) 2, 2-demethyl butane
(c) 1,1,1-trimethyl propane
(d) 2, 2-methyl butane
Answer. (b) 2, 2-demethyl butane

Question. Which of the following is the molecular formula of cyclobutane?
a) C₄H₁₀
b) C₄H₆
c) C₄H₈
d) C₄H₄
Answer. (c) C4H8

Explanation: Cyclobutane is a cyclic hydrocarbon consisting of four carbon atoms where each carbon atom is attached to the two other carbon atoms and two hydrogen atoms, as shown below:

Choose the correct statement:

Question. (a) The ethene molecule is made up of 2 carbon atoms and 4 hydrogen atoms.
(b) Each carbon atom shares three electrons with three hydrogen atoms to form three carbonhydrogen
single covalent bonds.
(c) In ethane, the two carbon atoms share one pair of electrons among themselves to form
one carbon-carbon single covalent bond.
(d) All the above.
Answer. (d) All the above

Question. Which of the following is not a characteristic of fullerenes?
(a) Of all the fullerene, C60 allotrope is the most stable.
(b) Its shape is similar to that of a soccer ball.
(c) It contains only fused six-membered carbon-carbon rings.
(d) Its hardness is lower than that of diamond.
Answer. (c) It contains only fused six-membered carbon-carbon rings.

Question. Which of the following statements about carbon is incorrect?
(a) It has four electrons in the valence shell.
(b) The four valencies of carbon do not lie in plane.
(c) The angle between any two adjacent valencies is 109.50.
(d) Three valencies of carbon are inclined to one another at an angle of 1200 while fourth is
perpendicular to the plane containing the remaining three valencies.
Answer. (d) Three valencies of carbon are inclined to one another at an angle of 1200 while fourth is perpendicular to the plane containing the remaining three valencies.

ASSERTION AND REASON

DIRECTION: In the following questions, a statement of assertion (A) is followed by a statement of
reason (R). Mark the correct choice as:
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.

Question. Assertion: Cyclopropane is heterocyclic compound.
Reason: Cyclopropane comes into category of those compounds in which complete ring is formed by carbon atoms only.
Answer. (d) Assertion (A) is false but reason (R) is true.

Question. Assertion: Branched-chain alkanes have lower boiling points.
Reason: As molecular size decreases, boiling point increases.
Answer. (c) Assertion (A) is true but reason (R) is false.
Boiling point increases with increase in molecular mass and surface area of the compound. With the increase of branching surface area decreases and hence the boiling point.

Question. Assertion: Olefins have the general formula C_nH_2n
Reason: There is one triple bond between two carbon atoms in their molecules.
Answer. (c) Assertion (A) is true but reason (R) is false.

Question. Assertion: Ionic compounds are solid in nature.
Reason: Ions are closely packed in 3-D crystal lattice structure.
Answer. (a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

Question. Assertion: Carbon shows maximum catenation property in the periodic table.
Reason: Carbon has small size and thus, forms strong C - C bond.
Answer. (a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

VERY SHORT ANSWER TYPE QUSTIONS (1 MARK)

Question. Name the product formed when a mixture of ammonium chloride and potassium cyanate is heated? Is the product, an ionic or a covalent compound?
Answer. Urea. It is a covalent compound.

Question. What is the valency of carbon in CH₃-CH₃ and CH₂=CH₂?
Answer. The valency of carbon in all its compounds whether saturated or unsaturated is 4.

SHORT ANSWER TYPE QUESTIONS (2 MARKS)

Question. Compare the ability of catenation of carbon and silicon. Give reasons.
Answer. Hints: Strength of C-C bond > Si-Si bond

Question. Explain the following:
(a) Diamond does not conduct electricity.
(b) Diamond is used for making tools for cutting and drilling.
Answer. Hints: (a) No free electrons
(b) Diamond has the highest thermal conductivity of any known substance.

Question. (a) How can diamonds be made artificially? How do synthetic diamonds differ from natural ones?
(b) Give any two differences between the properties of diamond and graphite. What causes these differences?
Answer. (a) Diamonds can be made artificially by subjecting pure carbon to very high pressure and temperature. The synthetic diamonds are small whereas natural diamonds are big.
(b) (i) Diamond is hard whereas graphite is soft.
(ii) Diamond is a non-conductor of electricity whereas graphite is a good conductor of electricity.
The difference in the physical properties of diamond and graphite arises because of the different arrangements of carbon atoms in them.