Phenols - acidity and electrophilic substitution — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Phenol is more acidic than cyclohexanol mainly because

• A. the phenoxide ion is resonance-stabilised
• B. phenol has no O-H bond
• C. cyclohexanol is aromatic
• D. phenol cannot lose a proton

Question 2 · difficulty L2 · understanding

What amount of bromine will be required to convert 2 g of phenol into 2,4,6-tribromophenol? (Given molar mass in $\mathrm{g} \mathrm{mol}^{-1}$ of $\mathrm{C}, \mathrm{H}, \mathrm{O}, \mathrm{Br}$ are $12,1,16,80$ respectively )

• A. 6.0 g
• B. 10.22 g
• C. 20.44 g
• D. 4.0 g

Question 3 · difficulty L2 · understanding

Which one the following compounds will readily react with dilute $$\mathrm{NaOH}$$ ?

• A. $$\mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{OH}$$
• B. $$\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$$
• C. $$\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}$$
• D. $$\left(\mathrm{CH}_3\right)_3 \mathrm{COH}$$

Question 4 · difficulty L2 · understanding

Given below are two statement : Statements I : Bromination of phenol in solvent with low polarity such as $$\mathrm{CHCl}_3$$ or $$\mathrm{CS}_2$$ requires Lewis acid catalyst. Statements II : The Lewis acid catalyst polarises the bromine to generate $$\mathrm{Br}^{+}$$. In the light of the above statements, choose the correct answer from the options given below :

• A. Statement I is true but Statement II is false
• B. Both Statement I and Statement II are true
• C. Statement I is false but Statement II is true
• D. Both Statement I and Statement II are false

Question 5 · difficulty L2 · understanding

Common name of Benzene - 1,2 - diol is -

• A. catechol
• B. quinol
• C. o-cresol
• D. resorcinol

Question 6 · difficulty L2 · understanding

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A: $$\mathrm{pK}_{\mathrm{a}}$$ value of phenol is 10.0 while that of ethanol is 15.9 . Reason R: Ethanol is stronger acid than phenol. In the light of the above statements, choose the correct answer from the options given below:

• A. A is false but R is true.
• B. Both $$A$$ and $$R$$ are true but $$R$$ is NOT the correct explanation of $$A$$.
• C. Both $$\mathrm{A}$$ and $$\mathrm{R}$$ are true and $$\mathrm{R}$$ is the correct explanation of $$\mathrm{A}$$.
• D. $$A$$ is true but $$R$$ is false.

Question 7 · difficulty L2 · understanding

Phenol treated with chloroform in presence of sodium hydroxide, which further hydrolyzed in presence of an acid results

• A. Salicylic acid
• B. Benzene-1,2-diol
• C. 2-Hydroxybenzaldehyde
• D. Benzene-1,3-diol

Question 8 · difficulty L2 · understanding

Match List I with List II List - I (Compound) List - II ($$\mathrm{pK_a}$$ value) (A) Ethanol (I) 10.0 (B) Phenol (II) 15.9 (C) m-Nitrophenol (III) 7.1 (D) p-Nitrophenol (IV) 8.3 Choose the correct answer from the options given below:

• A. A-I, B-II, C-III, D-IV
• B. A-IV, B-I, C-II, D-III
• C. A-II, B-I, C-IV, D-III
• D. A-III, B-IV, C-I, D-II

Question 9 · difficulty L2 · understanding

Phenolic group can be identified by a positive:

• A. Tollen's test
• B. Phthalein dye test
• C. Carbylamine test
• D. Lucas test

Question 10 · difficulty L2 · understanding

Given below are two statements : Statement (I) : p-nitrophenol is more acidic than m-nitrophenol and o-nitrophenol. Statement (II) : Ethanol will give immediate turbidity with Lucas reagent. In the light of the above statements, choose the correct answer from the options given below :

• A. Statement I is true but Statement II is false
• B. Both Statement I and Statement II are true
• C. Both Statement I and Statement II are false
• D. Statement I is false but Statement II is true