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1

### JEE Main 2021 (Online) 27th August Morning Shift

In polythionic acid, H2SxO6 (x = 3 to 5) the oxidation state(s) of sulphur is/are :
A
+ 5 only
B
+ 6 only
C
+ 3 and + 5 only
D
0 and + 5 only

## Explanation

2

### JEE Main 2021 (Online) 26th August Evening Shift

The number of non-ionisable hydrogen atoms present in the final product obtained from the hydrolysis of PCl5 is :
A
0
B
2
C
1
D
3

## Explanation

Here all hydrogens are ionisable.

$$\therefore$$ Answer is zero.
3

### JEE Main 2021 (Online) 27th July Evening Shift

Match List - I with List - II :

List - I
(compound)
List - II
(effect/affected species)
(a) Carbon monoxide (i) Carcinogenic
(b) Sulphur dioxide (ii) Metabolized by pyrus plants
(c) Polychlorinated biphenyls (iii) haemoglobin
(d) Oxides of Nitrogen (iv) Stiffness of flower buds

Choose the correct answer from the options given below :
A
(a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)
B
(a) - (iv), (b) - (i), (c) - (iii), (d) - (ii)
C
(a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)
D
(a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)

## Explanation

A. If haemoglobin binds CO, it prevents the binding of O2 to haemoglobin due to the competition for same binding sites.

B. Higher conc. SO2 in air can cause stiffness of flower buds.

C. Polychlorinated biphenyls are carcinogenic (cancer causing) in humans as well as animals.

D. Certain plants, e.g. pinus, Juniparus, quercus, pyrus and vitis can metabolise nitrogen oxides. Hence, the correct match is

(a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)
4

### JEE Main 2021 (Online) 27th July Evening Shift

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : SO2(g) is absorbed to a large extent than H2(g) on activated charcoal.

Reason R : SO2(g) has a higher critical temperature than H2(g).

In the light of the above statements, choose the most appropriate answer from the options given below.
A
Both A and R are correct but R is not the correct explanation of A.
B
Both A and R are correct and R is the correct explanation of A.
C
A is not correct but R is correct.
D
A is correct but R is not correct.

## Explanation

Gases having higher critical temperature absorb to a greater extent.

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