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JEE Main

Explore popular questions from pBlock Elements for JEE Main. This collection covers pBlock Elements previous year JEE Main questions hand picked by experienced teachers.

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Q 1. Ammonia reacts with excess of chlorine to form:

A

{tex} \mathrm { NH } _ { 3 } {/tex} and {tex} \mathrm { N } _ { 2 } {/tex}

{tex} \mathrm { NCl } _ { 3 } {/tex} and {tex} \mathrm { HCl } {/tex}

C

{tex} \mathrm { NCl } _ { 3 } {/tex} and {tex} \mathrm { N } _ { 2 } {/tex}

D

{tex} \mathrm { NH } _ { 4 } \mathrm { Cl } {/tex} and {tex} \mathrm { N } _ { 2 } {/tex}

Explanation

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Q 2. Amorphous boron is extracted from borax by following steps:
Borax{tex} \stackrel { ( x ) } { \longrightarrow } \mathrm { H } _ { 3 } \mathrm { BO } _ { 3 } \stackrel { \Delta } { \longrightarrow } \mathrm { B } _ { 2 } \mathrm { O } _ { 3 } \stackrel { ( \mathrm { Y } ) } { \longrightarrow } _ { \text {Boron } } {/tex}
Then {tex} \mathrm { X } {/tex} and {tex} \mathrm { Y } {/tex} are:

{tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } , \mathrm { Mg } {/tex}

B

{tex} \mathrm { HCl } , \mathrm { C } {/tex}

C

{tex} \mathrm { HCl } , \mathrm { Fe } {/tex}

D

{tex} \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } , \mathrm { Al } {/tex}

Explanation

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Q 3. Which one of the following properties is not shown by NO?

A

It combines with oxygen to from nitrogen dioxide.

B

It's bond order is 2.5

It is diamagnetic in gaseous state.

D

It is a neutral oxide.

Explanation

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Q 4. The number of lone pairs, and the number of {tex} \mathrm { S } - \mathrm { S } {/tex} bonds in {tex} \mathrm { S } _ { 8 } {/tex} molecules are respectively:

A

8,8

16,8

C

8,16

D

{tex} 8,4 {/tex}

Explanation