Aldehydes And Ketones(11th And 12th > Chemistry ) Questions and answers for exam Preparation

11th And 12th > Chemistry

ALDEHYDES AND KETONES MCQs

Total Questions : 30 | Page 1 of 3 pages

Identify Z in the series, $C H_{3} C H O M n O_{4}^{-} - ----- \to D i l . H_{2} S O_{4} X S O C l_{2} - --- \to Y C H_{3} C O O N a - ------- \to H e a t Z :$

$C H_{3} . C O . C H_{2} C O O N a$
$(C H_{3} C O)_{2} O$
$C H_{2} C l . C O . O . C O C H_{3}$
$C H C l_{2} . C O . O . C O C H_{3}$

Discuss Question

Answer: Option B. ->

(C H_{3} C O)_{2} O

:
B

$H_{3} C - C H O M n O_{4}^{-} - ---- \to d i l . H_{2} S O_{4} H_{3} C - C O O H S O C l_{2} - --- \to H_{3} C - C O C l C H_{3} C O O N a - ------- \to$

Question 2.

A compound A has molecular formula $C_{2} C l_{3} O H$ . It reduces Fehling’s solution and on oxidation gives a monocarboxylic acid B. A is obtained by action of $C l_{2}$ on ethyl alcohol. A is:

chloral
$C H C l_{3}$
$C H_{3} C l$
chloro acetic acid

Discuss Question

Answer: Option A. -> chloral
:
A

Chlorine reduces Fehling’s solution due to the aldehyde group that converts to $- C O O H$ group

Question 3.

The increasing order of the rate of HCN addition to compounds A-D is:

(A) $H C H O$ (B) $C H_{3} C O C H_{3}$

$A < B < C < D$
$D < B < C < A$
$D < C < B < A$
$C < D < B < A$

Discuss Question

Answer: Option C. ->

D < C < B < A

:
C

Due to steric hindrance

Question 4.

The correct order of acid strength is:

$C H_{3} C O O H > C H_{2} C l C O O H > C H C l_{2} C O O H$
$C H C l_{2} C O O H > C H_{2} C l C O O H > C H_{3} C O O H$
$C H C l_{2} C O O H > C H_{3} C O O H > C H_{2} C l C O O H$
$C H_{2} C l C O O H > C H_{3} C O O H > C H C l_{2} C O O H$

Discuss Question

Answer: Option B. ->

C H C l_{2} C O O H > C H_{2} C l C O O H > C H_{3} C O O H

:
B

Greater the number of –I groups on the α-carbon, acidic nature increases .

Question 5.

A ketone reacted with $C_{2} H_{5} M g B r$ reagent followed by hydrolysis gave a product which on dehydration gives an alkene. The alkene on ozonolysis gave diethyl ketone and acetaldehyde. The ketone is:

dimethyl ketone
ethyl methyl ketone
diethyl ketone
ethyl propyl ketone

Discuss Question

Answer: Option C. -> diethyl ketone
:
C

Question 6.

$C H_{3} C H O + C H_{2} (C O O H)_{2} △ - --- \to P y r i d i n e X; X$ is :

$C H_{3} C O O H$
$C_{2} H_{5} C O O H$
$C H_{3} C H C H C O O H$
$(C O O H) C H C H (C O O H)$

Discuss Question

Answer: Option C. ->

C H_{3} C H C H C O O H

:
C

Question 7.

$C H_{3} C H O + H_{2} N O H - \to C H_{3} C H = N - O H$ The above reaction occurs at:

pH = 1
pH = 4.5
any value of pH
pH = 12

Discuss Question

Answer: Option B. -> pH = 4.5
:
B

In highly acidic medium, $N H_{2} O H$ forms salt with the acid molecules and loses its ability to act as a nucloephile.

Question 8.

In a set of reactions propionic acid yielded a compound D. $C H_{3} C H_{2} C O O H S O C l_{2} - --- \to B N H_{3} - -- \to C K O H - -- \to B r_{2} D$ The structure of D would be: