An unknown mixture contains one or two of the following : CaCO3, BaCl2, AgNO3, Na2SO4, ZnSO4 and NaOH. The mixture is completely soluble in water and solution gives pink colour with phenolphthalein. W

Question

An unknown mixture contains one or two of the following : CaCO3, BaCl2, AgNO3, 
Na2SO4, ZnSO4 and NaOH. The mixture is completely soluble in water and solution 
gives pink colour with phenolphthalein. When dilute hydrochloric acid is 
gradually added to the solution, a precipitate is formed which dissolves with 
further addition of the acid.

Prashant Kotian · Accepted Answer

Correct answer: C. The soluble Na2ZnO2 reacts with dil. HCl to first precipitate Zn(OH)2 (white), which then dissolves in excess HCl to form soluble ZnCl2.

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