When a substance `A` reacts with water it produces a conbustible gas `B` and a solution of substance `C` in water. When another substance `D` reacts with this soution of `C`, it also produces the same gas `B` on warming but `D` can produce `B` on reaction with dilute sulphuric acid at room temperature. `B` on reaction with dilute sulphuric acid at room tempreture. `A` imparts a golden yellow colour to a smokeless flame of bunsen flame. `A,B,C` and `D` are respectively.

Options

A. `Na,H_(2),NaOH, Zn`
B. `K, H_(2),KOH, Al`
C. `Ca,H_(2), Ca(OH)_(2), Sn`
D. `CaC_(2), C_(2)H_(2),Ca(OH)_(2),Fe`

Answer

A

Explanation

`underset(A)(2Na) + 2H_(2)O to underset(B)(H_(2))+2ZnO_(2) + underset(C)(2NaOH) and underset(D)(Zn)+underset(C)(NaOH) to Na_(2)ZnO_(2) + underset(B)(H_(2)) underset(D)Zn+ H_(2)SO_(4)("dil.") to ZnSO_(4) + underset(B)(H_(2))`
Since Na gives golden yellow flame, K gives pink violet flame while Ca gives brick red flame, therefore, option (a) is correct.