An unknown mixture contains one or two of the following: `CaCO_(3),BaCl_(2),AgNO_(3),Na_(2)SO_(4),ZnSO_(4) 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 dissolved with further addition of the acid.
Q. The white precipitate is

Options

A. `ZnSO_(4)`
B. `Zn_(2)ZnO_(2)`
C. `Zn(OH)_(2)`
D. `ZnCl_(2)`

Answer

C

Explanation

Mixture contains `NaOH+ZnSO_(4)`
`NaOH+ZnSO_(4) to underset("soluble")(Na_(2)ZnO_(2))+Na_(2)SO_(4)+2H_(2)O`
`Na_(2)ZnO_(2)+2HCl to 2NaCl+Zn(OH)_(2)darr`
`Zn(OH)_(2)+2HCl to underset("soluble")(ZnCl_(2))+2H_(2)O`