Practice problems on JEE Mains, JEE Mains 2021 Feb 25 Shift 1

Question 1

The solubility ofAgCN in a buffer solution of pH=3 is x . The value of x is :[Assume: No cyano complex is formed; Ksp​(AgCN)=2.2×10−16 and Ka​(HCN)= 6.2×10−10]

Accepted Answer

1.9×10−6

Answer

1.6×10−6

Answer

2.2×10−16

Answer

0.625×10−6

Question 2

The hybridization and magnetic nature of [Mn(CN)6​]4 and [Fe(CN)6​]3− , respectively are

Accepted Answer

d2sp3 and paramagnetic

Answer

d2sp3 and diamagnetic

Answer

sp3 d2 and paramagnetic

Answer

sp3 d2 and diamagnetic

Question 3

A man is observing, from the top of a tower, a boat speeding towards the tower from a certain point A, with uniform speed. At the point, angle of depression of the boat with the man's eye is 30∘ (Ignore man's height). After sailing for 20 seconds, towards the base of the tower (which is at the level of water), the boat has reached a point B, where the angle of depression is 45∘ . Then the time taken (in seconds) by the boat from B to reach the base of the tower is:

Accepted Answer

10(3​+1)

Answer

103​

Answer

10

Answer

10(3​−1)

Question 4

A 5 V battery is connected across the points X and Y. Assume D1​ and D2​ to be normal silicon diodes. Find the current supplied by the battery if the +ve terminal of the battery is connected to point X.

Accepted Answer

∼0.43 A

Answer

∼1.5 A

Answer

∼0.5 A

Answer

∼0.86 A

Question 5

The major product of the following chemical reaction is:

Accepted Answer

CH3​CH2​CHO

Answer

CH3​CH2​CH3​

Answer

CH3​CH2​CH2​OH

Answer

(CH3​CH2​CO)2​O

Question 6

Which of the glycosidic linkage between galactose and glucose is present in lactose?

Accepted Answer

C-1 of galactose and C-4 of glucose

Answer

C-1 of glucose and C-6 of galactose

Answer

C-1 of galactose and C-6 of glucose

Answer

C-1 of glucose and C-4 of galactose

Question 7

Which of the following reaction/s will not give p-aminoazobenzene ?

Accepted Answer

B only

Answer

C only

Answer

A only

Answer

A and B

Question 8

Compound(s) which will liberate carbon dioxide with sodium bicarbonate solution is/ are:

Accepted Answer

B and C only

Answer

B only

Answer

C only

Answer

A and B only

Question 9

Given below are two statements:Statement-I : An allotrope of oxygen is an important intermediate in the formation of reducing smog.Statement-II: Gases such as oxides of nitrogen and sulphur present in troposphere contribute to the formation of photochemical smog.In the light of the above statements, choose the correct answer from the options given below:

Accepted Answer

Cr+ and Mn2+

Answer

Ni2+ and Cu+

Answer

Fe2+ and Co+

Answer

V2+ and Cr+

Question 10

Given below are two statements:Statement-I : An allotrope of oxygen is an important intermediate in the formation of reducing smog.Statement-II: Gases such as oxides of nitrogen and sulphur present in troposphere contribute to the formation of photochemical smog.In the light of the above statements, choose the correct answer from the options given below:

Accepted Answer

Both Statement I and Statement II are false

Answer

Statement I is true but Statement II is false

Answer

Statement I is false but Statement II is true

Answer

Both Statement I and Statement II are true

Question 11

Which statement is correct?

Accepted Answer

Synthesis of Buna-S needs nascent oxygen

Answer

Buna-S is a synthetic and linear thermosetting polymer.

Answer

Buna- N is a natural polymer

Answer

Neoprene is an addition copolymer used in plastic bucket manufacturing

Question 12

The correct statement about B2​H6​ is :

Accepted Answer

Terminal B - H bonds have less p-character when compared to bridging bonds

Answer

All B- H-B angles are of 120∘

Answer

The two B−H−B bonds are not of same length

Answer

Its fragment, BH3​ , behaves as a Lewis base

Question 13

According to molecular orbital theory, the species among the following that does not exist is

Accepted Answer

Be2​

Answer

He2−​

Answer

He2+​

Answer

O22−​