Science (English Medium) Class 12 - CBSE Question Bank Solutions for Chemistry

Mark the correct increasing order of reactivity of the following compounds with HBr/HCl.

(a)
(b)
(c)

Name the factors responsible for the solubility of alcohols in water.

Suggest a reagent for the following conversion.

Alcohols react with active metals e.g. Na, K etc. to give corresponding alkoxides. Write down the decreasing order of reactivity of sodium metal towards primary, secondary and tertiary alcohols.

Explain why is OH group in phenols more strongly held as compared to OH group in alcohols.

Explain why nucleophilic substitution reactions are not very common in phenols.

In Kolbe’s reaction, instead of phenol, phenoxide ion is treated with carbon dioxide. Why?

Ethers can be prepared by Williamson synthesis in which an alkyl halide is reacted with sodium alkoxide. Di-tert-butyl ether can’t be prepared by this method. Explain.

Why is the C – O – H bond angle in alcohols slightly less than the tetrahedral angle whereas the C – O – C bond angle in ether is slightly greater?

Assertion: Bond angle in ethers is slightly less than the tetrahedral angle.

Reason: There is a repulsion between the two bulky (–R) groups.

The gas evolved when methylamine reacts with nitrous acid is:

Acid anhydrides on reaction with primary amines give ______.

Carbohydrates are essential for life in both plants and animals. Name the carbohydrates that are used as storage molecules in plants and animals, also name the carbohydrate which is present in wood or in the fibre of cotton cloth.

Which of the following are example of synthetic rubber?

(i) Polychloroprene

(ii) Polyacrylonitrile

(iii) Buna-N

(iv) cis-polyisoprene

Vulcanisation makes rubber:

(i) more elastic

(ii) soluble in inorganic solvent

(iii) crystalline

(iv) more stiff

Identify the polymer given below:

Match materials given in Column I with the polymers given in Column II.

Solutions of two electrolytes ‘A’ and ‘B’ are diluted. The Λ_m of ‘B’ increases 1.5 times while that of A increases 25 times. Which of the two is a strong electrolyte? Justify your answer. Graphically show the behavior of ‘A’ and ‘B’.

The molar conductivity of CH₃COOH at infinite dilution is 390 Scm²/mol. Using the graph and given information, the molar conductivity of CH₃COOK will be:

Which of the following statements is not correct for amines?