Question

When $$C{l_2}$$  gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from

A. zero to + 1 and zero to - 5
B. zero to - 1 and zero to + 5  
C. zero to - 1 and zero to + 3
D. zero to + 1 and zero to - 3
Answer :   zero to - 1 and zero to + 5
Solution :
When chlorine gas reacts with hot and concentrated $$NaOH$$   solution, it disproportionates into chloride $$\left( {C{l^ - }} \right)$$  and chlorate $$\left( {ClO_3^ - } \right)$$  ions.
P - Block Elements mcq solution image
In this process, oxidation number of chlorine changes from 0 to - 1 and 0 to + 5.
NOTE
In disproportionation reactions, the same element undergoes oxidation as well as reduction.

Releted MCQ Question on
Inorganic Chemistry >> P - Block Elements

Releted Question 1

The reddish brown coloured gas formed when nitric oxide is oxidised by air is

A. $${N_2}{O_5}$$
B. $${N_2}{O_4}$$
C. $$N{O_2}$$
D. $${N_2}{O_3}$$
Releted Question 2

The temporary hardness of water due to calcium carbonate can be removed by adding —

A. $$CaC{O_3}$$
B. $$Ca{\left( {OH} \right)_2}\,$$
C. $$CaC{l_2}$$
D. $$\,HCl$$
Releted Question 3

Which of the following is most stable to heat

A. $$HCl$$
B. $$HOCl$$
C. $$HBr$$
D. $$HI$$
Releted Question 4

White $$P$$ reacts with caustic soda. The products are $$P{H_3}$$ and $$Na{H_2}P{O_2}.$$   This reaction is an example of

A. Oxidation
B. Reduction
C. oxidation and reduction
D. Neutralisation

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P - Block Elements


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