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in Chemistry by (56.7k points)

An aqueous solution of salt containing an acidic radical X reacts with sodium hypochlorite in neutral medium. The gas evolved produces blue black colour spot on the starch paper. The anion X– is :

(A) CH3COO 

(B) Br

(C) I– 

(D) NO2

1 Answer

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Best answer

Correct Answer is: (B) Br 

OCl + 3I + H2O → I3 + 2OH + Cl

I3 + starch → blue -black spot on starch paper appears due to the formation of iodine starch adsorption complex.

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