Carbon and Its Compounds Part 4: MCQs (Q76–Q100)

🧪 Carbon and Its Compounds – Class 10 Science MCQs

Part 4: HOTS, Numericals & Real-Life Applications (Q76–Q100)

Q76. Which property makes carbon form millions of compounds?

A. Allotropy
B. Low atomic number
C. Catenation and tetravalency
D. High density

✅ Correct Answer: C. Catenation and tetravalency

Q77. Which compound is called wood alcohol?

A. Methanol
B. Ethanol
C. Propanol
D. Butanol

✅ Correct Answer: A. Methanol

Methanol is poisonous, used as industrial solvent.

Q78. Which compound is used as an antiseptic in hospitals?

A. Ethanol (70%)
B. Methanol
C. Ethanoic acid
D. Chloroform

✅ Correct Answer: A. Ethanol (70%)

Q79. Which product is formed when methane reacts with chlorine in presence of sunlight?

A. CO₂
B. CH₃Cl
C. CH₃OH
D. CH₃COOH

✅ Correct Answer: B. CH₃Cl (Chloromethane)

Substitution reaction.

Q80. Why is graphite a conductor of electricity but diamond is not?

A. Diamond has impurities
B. Graphite has free electrons
C. Graphite is soft, diamond is hard
D. Both contain metals

✅ Correct Answer: B. Graphite has free electrons

Q81. Which carbon compound is used in the manufacture of perfumes and esters?

A. Alcohols
B. Carboxylic acids
C. Esters
D. Aldehydes

✅ Correct Answer: C. Esters

Q82. Which reaction is responsible for rancidity of oils?

A. Reduction
B. Oxidation
C. Addition
D. Substitution

✅ Correct Answer: B. Oxidation

Q83. Which reaction is used in breathing oxygen masks of mountaineers?

A. Alcohol fermentation
B. Combustion of hydrocarbons
C. Decomposition of KClO₃
D. Combustion of coal

✅ Correct Answer: C. Decomposition of KClO₃ → releases O₂

Q84. Which carbon compound is used as a preservative in pickles?

A. Methanol
B. Ethanol
C. Ethanoic acid
D. Esters

✅ Correct Answer: C. Ethanoic acid

Q85. Which of the following is an unsaturated hydrocarbon?

A. CH₄
B. C₂H₆
C. C₂H₄
D. C₃H₈

✅ Correct Answer: C. C₂H₄ (Ethene)

Q86. Which gas is evolved when ethanol reacts with sodium?

A. O₂
B. H₂
C. CO₂
D. CH₄

✅ Correct Answer: B. H₂

Q87. Which of the following gives a brisk effervescence with sodium carbonate?

A. Alcohol
B. Carboxylic acid
C. Aldehyde
D. Ketone

✅ Correct Answer: B. Carboxylic acid

Q88. Which of the following decolorizes bromine water?

A. CH₄
B. C₂H₆
C. C₂H₄
D. C₆H₁₄

✅ Correct Answer: C. C₂H₄

Unsaturated hydrocarbons decolorize bromine water (test for unsaturation).

Q89. Which of these is an industrial use of ethanol?

A. Solvent for varnishes
B. Making alcoholic drinks
C. Used in hand sanitizers
D. All of these

✅ Correct Answer: D. All of these

Q90. Which product is formed when ethanoic acid reacts with ethanol?

A. Soap
B. Ester
C. Ethene
D. Aldehyde

✅ Correct Answer: B. Ester

Q91. Which test is used to detect carboxylic acid group?

A. Brisk effervescence with NaHCO₃
B. Bromine water test
C. Litmus test only
D. Reaction with NaCl

✅ Correct Answer: A. Brisk effervescence with NaHCO₃

Q92. Which carbon compound is added to soft drinks?

A. Carbon dioxide (dissolved)
B. Methanol
C. Ethanoic acid
D. Esters

✅ Correct Answer: A. CO₂ (carbonated drinks)

Q93. Which fuel is called bioethanol?

A. Methane
B. Ethanol
C. LPG
D. Butane

✅ Correct Answer: B. Ethanol

Ethanol from fermentation used as eco-friendly fuel.

Q94. Which gas is evolved in saponification reaction?

A. CO₂
B. H₂
C. None
D. O₂

✅ Correct Answer: C. None

Soap + Glycerol formed, no gas released.

Q95. Why does soap not form lather in hard water?

A. It evaporates
B. Reacts with Ca²⁺, Mg²⁺ ions to form scum
C. Soap dissolves completely
D. Soap is unstable

✅ Correct Answer: B. Reacts with Ca²⁺, Mg²⁺ ions to form scum

Q96. Which hydrocarbon gives the highest amount of heat per gram on combustion?

A. Alkynes
B. Alkanes
C. Alkenes
D. Aromatics

✅ Correct Answer: B. Alkanes

Saturated hydrocarbons burn completely → max heat.

Q97. Which of the following is NOT a use of esters?

A. Flavouring agents
B. Perfumes
C. Soap making
D. Antiseptics

✅ Correct Answer: D. Antiseptics

Q98. Which property makes detergents better than soaps in hard water?

A. Detergents are cheaper
B. Detergents do not form scum
C. Detergents are biodegradable
D. Detergents have more lather

✅ Correct Answer: B. Detergents do not form scum

Q99. Which carbon compound is the main constituent of vinegar?

A. CH₃OH
B. CH₃CH₂OH
C. CH₃COOH
D. CH₃CHO

✅ Correct Answer: C. CH₃COOH (Acetic acid)

Q100. Which statement is correct about carbon?

A. Carbon forms ionic bonds
B. Carbon shows catenation and tetravalency
C. Carbon always forms metallic bonds
D. Carbon has valency 2

✅ Correct Answer: B. Carbon shows catenation and tetravalency

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