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1

JEE Main 2021 (Online) 27th August Evening Shift

MCQ (Single Correct Answer)
Potassium permanganate on heating at 513 K gives a product which is :
A
paramagnetic and colourless
B
diamagnetic and green
C
diamagnetic and colourless
D
paramagnetic and green

Explanation

$$2KMn{O_4}\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{200^\circ C}^\Delta } \mathop {{K_2}Mn{O_4}}\limits_{Green} + \mathop {Mn{O_2}}\limits_{Black} + {O_2}$$

In K2MnO4, manganese oxidation state is +6 and hence it has one unpaired e$$-$$.
2

JEE Main 2021 (Online) 27th August Morning Shift

MCQ (Single Correct Answer)
The nature of oxides V2O3 and CrO is indexed as 'X' and 'Y' type respectively. The correct set of X and Y is :
A
X = basic Y = amphoteric
B
X = amphoteric Y = basic
C
X = acidic Y = acidic
D
X = basic Y = basic

Explanation

V2O3 basic

CrO basic
3

JEE Main 2021 (Online) 26th August Morning Shift

MCQ (Single Correct Answer)
The incorrect statement is :
A
Cl2 is more reactive than ClF.
B
F2 is more reactive than ClF.
C
On hydrolysis ClF forms HOCl and HF.
D
F2 is a stronger oxidizing agent than Cl2 in aqueous solution.

Explanation

(i) Reactivity order :

F2 > ClF (inter halogen) > Cl2

(ii) ClF + H2O $$\to$$ HOCl + HF

(iii) Oxidizing power is aqueous solution

F2 > Cl2 > Br2 > I2
4

JEE Main 2021 (Online) 27th July Morning Shift

MCQ (Single Correct Answer)
Match List - I with List - II :

List - I List - II
(a) NaOH (i) Acidic
(b) $$Be{(OH)_2}$$ (ii) Basic
(c) $$Ca{(OH)_2}$$ (iii) Amphoteric
(d) $$B{(OH)_3}$$
(e) $$Al{(OH)_3}$$


Choose the most appropriate answer from the options given below
A
(a)-(ii), (b)-(ii), (c)-(iii), (d)-(ii), (e)-(iii)
B
(a)-(ii), (b)-(iii), (c)-(ii), (d)-(i), (e)-(iii)
C
(a)-(ii), (b)-(ii), (c)-(iii), (d)-(i), (e)-(iii)
D
(a)-(ii), (b)-(i), (c)-(ii), (d)-(iii), (e)-(iii)

Explanation

NaOH $$\to$$ Basic

Be(OH)2 $$\to$$ Amphoteric

Ca(OH)2 $$\to$$ Basic

B(OH)3 $$\to$$ Acidic

Al(OH)3 $$\to$$ Amphoteric

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