JEE MAIN - Chemistry (2021 - 31st August Morning Shift)

1
The correct order of reactivity of the given chlorides with acetate in acetic acid is :
Answer
(D)
2
In the structure of the dichromate ion, there is a :
Answer
(B)
non-linear symmetrical Cr-O-Cr bond.
3
Which one of the following compounds contains $$\beta$$-C1-C4 glycosidic linkage?
Answer
(A)
Lactose
4
The major products A and B in the following set of reactions are :

JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Compounds Containing Nitrogen Question 108 English
Answer
(B)
JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Compounds Containing Nitrogen Question 108 English Option 2
5
Which one of the following lanthanides exhibits +2 oxidation state with diamagnetic nature? (Given Z for Nd = 60, Yb = 70, La = 57, Ce = 58)
Answer
(B)
Yb
6
The major product formed in the following reaction is :

Answer
(A)
JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Alcohols, Phenols and Ethers Question 87 English Option 1
7
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Treatment of bromine water with propene yields 1-bromopropan-2-ol.

Reason (R) : Attack of water on bromonium ion follows Markovnikov rule and results in 1-bromopropan-2-ol.

In the light of the above statements, choose the most appropriate answer from the options given below :
Answer
(C)
Both (A) and (R) are true and (R) is the correct explanation of (A)
8
The denticity of an organic ligand, biuret is :
Answer
(A)
2
9
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Metallic character decreases and non-metallic character increases on moving from left to right in a period.

Reason (R) : It is due to increase in ionisation enthalpy and decrease in electron gain enthalpy, when one moves from left to right in a period.

In the light of the above statements, choose the most appropriate answer from the options given below :
Answer
(B)
(A) is true but (R) is false
10
Choose the correct name for compound given below :

JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Basics of Organic Chemistry Question 133 English
Answer
(C)
(2E)-2-Bromo-hex-2-en-4-yne
11
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R) :

Assertion (A) : A simple distillation can be used to separate a mixture of propanol and propanone.

Reason (R) : Two liquids with a difference of more than 20$$^\circ$$ in their boiling points can be separated by simple distillations.

In the light of the above statements, choose the most appropriate answer from the options given below :
Answer
(D)
Both (A) and (R) are correct and (R) is the correct explanation of (A).
12
Which one of the following 0.10 M aqueous solutions will exhibit the largest freezing point depression?
Answer
(D)
KHSO4
13
The structure of product C, formed by the following sequence of reactions is :

JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 111 English
Answer
(A)
JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 111 English Option 1
14
Consider the following cell reaction :

$$C{d_{(s)}} + H{g_2}S{O_{4(s)}} + {9 \over 5}{H_2}{O_{(l)}}$$ $$\rightleftharpoons$$ $$CdS{O_4}.{9 \over 5}{H_2}{O_{(s)}} + 2H{g_{(l)}}$$

The value of $$E_{cell}^0$$ is 4.315 V at 25$$^\circ$$C. If $$\Delta$$H$$^\circ$$ = $$-$$825.2 kJ mol$$-$$1, the standard entropy change $$\Delta$$S$$^\circ$$ in J K$$-$$1 is ___________. (Nearest integer) [Given : Faraday constant = 96487 C mol$$-$$1]
Answer
25
15
The molarity of the solution prepared by dissolving 6.3 g of oxalic acid (H2C2O4.2H2O) in 250 mL of water in mol L$$-$$1 is x $$\times$$ 10$$-$$2. The value of x is _____________. (Nearest integer) [Atomic mass : H : 1.0, C : 12.0, O : 16.0]
Answer
20
16
The total number of reagents from those given blow, that can convert nitrobenzene into aniline is ___________. (Integer answer)

I. Sn $$-$$ HCl

II. Sn $$-$$ NH4OH

III. Fe $$-$$ HCl

IV. Zn $$-$$ HCl

V. H2 $$-$$ Pd

VI. H2 $$-$$ Raney Nickel
Answer
5
17
For a first order reaction, the ratio of the time for 75% completion of a reaction to the time for 50% completion is ____________. (Integer answer)
Answer
2
18
The number of hydrogen bonded water molecule(s) associated with stoichiometry CuSO4.5H2O is ____________.
Answer
1
19
According to the following figure, the magnitude of the enthalpy change of the reaction

A + B $$\to$$ M + N in kJ mol$$-$$ is equal to ___________. (Integer answer)

JEE Main 2021 (Online) 31st August Morning Shift Chemistry - Chemical Kinetics and Nuclear Chemistry Question 84 English
Answer
45
20
Ge(Z = 32) in its ground state electronic configuration has x completely filled orbitals with ml = 0. The value of x is ___________.
Answer
7
21
A3B2 is a sparingly soluble salt of molar mass M (g mol$$-$$1) and solubility x g L$$-$$1. The solubility product satisfies $${K_{sp}} = a{\left( {{x \over M}} \right)^5}$$. The value of a is _____________. (Integer answer)
Answer
108