CBSE Class 10 Science Carbon and its Compounds MCQs Set I

Question. 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

Question. 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

Question. Identify the product formed when methane reacts with chlorine in the presence of sunlight is
(a) C₂Cl₆
(b) CH₃Cl
(c) CHCl₄
(d) None of these

Answer: B

Question. The compound which gives a brisk effervescence with sodium metal and not with sodium hydrogen carbonate is
(a) ethanol
(b) ethanoic acid
(c) both ethanoic acid and ethanol
(d) none of these

Answer: A

Question. The heteroatoms present is
CH₃ – O – CH₂ – CH₂ (Br)
(a) oxygen
(b) carbon
(c) hydrogen
(d) bromine

Answer: D

Question. The number of single and double bonds present in benzenes are
(a) 9 and 6
(b) 9 and 3
(c) 12 and 3
(d) 12 and 6

Answer: B

Question. The isomeric pair is
(a) ethane and propane
(b) propane and butane
(c) ethane and ethane
(d) butane and 2-methyl propane

Answer: D

Question. Vinegar is a solution of
(a) 30% – 40% acetic acid in alcohol
(b) 5% – 8% acetic acid in alcohol
(c) 5% – 8% acetic acid in water
(d) 15% – 20% acetic acid in water

Answer: C

Question. Which of the following is used to oxidise ethanol to ethanoic acid?
(a) Alkaline KMnO₄
(b) Conc. H₂SO₄
(c) Acidified K₂Cr₂O₇
(d) All of above

Answer: D

Question. Butanone is a four-carbon compound with the functional group
(a) carboxylic acid.
(b) aldehyde.
(c) ketone. 
(d) alcohol. 

Answer: C

Question. Covalent compounds
(a) have high melting and boiling points
(b) are mostly soluble in water
(c) are formed between atoms of metals and non-metals
(d) are formed by the sharing of electrons in the bonding atoms.

Answer: D

Question. Drinking alcohol and driving may cause serious accidents. To discourage this, police randomly test drivers for alcohol using a breath analyser. The breath analyser works because
(a) Alcohol makes the breath dry and the machine registers moisture
(b) Alcohol makes the breath hotter which changes the machine reading
(c) Alcohol causes more saliva which the machine checks.
(d) Alcohol in the breath cause a chemical change registered by the machine.

Answer: B

Question. Soaps are formed by saponification of
(a) alcohols
(b) glycosides
(c) simple esters
(d) carboxylic acids

Answer: C

Question. 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

Question. Acetic acid was added to a liquid X kept in a test tube. A colourless and odourless gas Y was evolved. The gas was passed through lime water which turned milky. It was concluded that:
(a) Liquid X is sodium hydroxide and the gas Y is CO₂
(b) Liquid X is sodium carbonate and the gas Y is CO₂
(c) Liquid X is sodium acetates and the gas Y is CO₂
(d) Liquid X is sodium chloride and the gas Y is SO₂.

Answer: B

Question. For gas welding used for welding broken pieces of iron, we normally use a mixture of
(a) Ethane and oxygen
(b) Ethene and oxygen
(c) Ethyne and oxygen
(d) Ethene and air

Answer: A

Question. Butanone is a four-carbon compound with the functional group
(a) carboxylic acid.
(b) aldehyde.
(c) ketone.
(d) alcohol.

Answer: D

Question. The by product of soap is
(a) isoprene
(b) glycerol
(c) butene
(d) ethylene glycol

Answer: B

Question. Which of the following can be used for the denaturation of ethyl alcohol?
(a) Methyl alcohol
(b) Pyridines
(c) Copper sulphate
(d) All of above

Answer: D

Question. Tertiary butane gets oxidised with oxidising agents like alkaline KMNO₄ to
(a) Isobutane
(b) Ter-butyl alcohol
(c) Secondary-propyl alcohol
(d) All of above

Answer: B

Question. Which is denatured spirit?
(a) ethanol only
(b) ethanol and methanol (50%)
(c) ethanol and methanol (5%)
(d) methanol only

Answer: C

Question. The substance not responsible for the hardness of water is
(a) sodium nitrate
(b) calcium hydrogen carbonate
(c) calcium carbonate
(d) magnesium carbonate

Answer: A

Question. The general formula for alkanes is CnH2ⁿ⁺¹–CHO. The value of ‘n’ for the first member.
(a) 1
(b) 0
(c) 0.5
(d) 1.1

Answer: B

Question. The upper and lower homologue of C₂H₅OH are respectively
(a) methyl alcohol and butyl alcohol
(b) ethyl alcohol and propyl alcohol
(c) butyl alcohol and propyl alcohol
(d) propyl alcohol and methyl alcohol

Answer: D

Question. Which is not true about homologous series?
(a) They have same general formula.
(b) They differ from other by CH₃ group.
(c) They have same functional group.
(d) They have same chemical properties.

Answer: B

Question. Bromine reacts with saturated hydrocarbon at room temperature in the
(a) absence of sunlight
(b) presence of water
(c) presence of sunlight
(d) presence of hydrochloric acid

Answer: C

Question. Ethanoic acid was added to sodium carbonate solution and the gas evolved was tested with a burning splinter. The following four observations were reported. Identify the correct observation.
(a) The gas burns with pop sound and the flame gets extinguished
(b) The gas does not burn but the splinter burns with pop sound
(c) The flame extinguishes and the gas does not burn
(d) The gas burns with a blue flame and the splinter burns brightly

Answer: C