WBJEE 2015 Solved Chemistry Question Paper Part 6

Find WBJEE 2015 Solved Chemistry Question Paper – Part 6 in this article. This paper consists of 5 questions (#66 to #70) from WBJEE 2015 Chemistry paper. Detailed solution of these questions has been provided so that students can match their solutions.

Importance of Previous Years’ Paper:

Previous years’ question papers help aspirants in understanding exam pattern, question format, important topics and assessing preparation. It has also been seen that sometimes questions are repeated in WBJEE Exam. So, this paper will certainly boost your confidence.

About WBJEE Exam

WBJEE is a common entrance examinations held at state level for admission to the Undergraduate Level Engineering and Medical courses in the State of West Bengal. The Chemistry section of WBJEE 2015 engineering entrance exam consists of 40 questions.

66. The ratio of volumes of CH₃COOH 0.1 (N) to CH₃COONa 0.1 (N) required to prepare a buffer solution of pH 5.74 is (given : pKa of CH₃COOH is 4.74)

(A) 10 : 1

(B) 5 : 1

(C) 1 : 5

(D) 1 : 10

Ans : (D)

Sol:

We have,

 pH = 5.74,

pKa = 4.74,

Let the volume of acid solution = x L,

Also, Volume of salt solution = y L

We have,

WBJEE 2016 Solved Physics and Chemistry Question Paper

67. The reaction of methyltrichloroacetate (Cl₃CCO₂Me) with sodium methoxide (NaOMe) generates

(A) Carbocation

(B) Cabene

(C) Carbanion

(D) Carbon radical

Ans : (B)

Sol:

68. Best reagent for nuclear iodination of aromatic compounds is

(A) KI/CH₃COCH₃

(B) I₂/CH₃CN

(C) KI/CH₃COOH

(D) I₂/HNO₃

Ans : (D)

Sol:

The best reagent for the iodination of aromatic compound is I₂/HNO₃

69. In the Lassaigne’s test for the detection of nitrogen in an organic compound, the appearance of blue coloured compound is due to

(A) ferric ferricyanide

(B) ferrous ferricyanide

(C) ferric ferrocyanide

(D) ferrous ferrocyanide

Ans : (C)

Sol:

Lassaigne’s test is conducted to detect the halogens, nitrogen and sulphur in an organic compound.

So, the appearance of blue coloured compound is due to ferric ferrocyanide.

70. In the following reaction

The product ‘P’ is

(A) RCHO

(B) R₂CHOE_t

(C) R₃CH

(D) RCH(OEt)₂

Ans : (A)

Sol:

The reaction can be written as:

Also Get:

WBJEE Sample Papers

WBJEE Previous Years' Question Papers

WBJEE Online Test