Question

A divalent metal salt X, which contributes to hardness of water, combines with washing soda and forms an insoluble salt Y and common salt. Salt Y is also used for the laboratory preparation of `CO_(2)`. Identify X and Y respectively.
A. `CaSO_(4), CaCO_(3)`
B. `MgSO_(4), MgCO_(3)`
C. `CaCl_(2), CaCO_(3)`
D. `MgCl_(2), MgCO_(3)`

Answer 1

Correct Answer - C
Divalent metal salt X which contributes to hardness of water is `CaCl_(2)` which combines with `Na_(2)CO_(3)` It gives salt Y calcium carbonate and sodium chloride.
`CaCl_(2)+Na_(2)CO_(3)rarrCaCO_(3)darr+2NaCl`