When a substance A reacts with water, it produces a combustible gas B and s solution of substance C in water. When another substance D reacts with this solution of C, it produces the same gas B on warming but D can produces gas B on reaction with dilute sulphuric acid at room temperature . A imparts a deep golden yellow colour to a smokeless flame of Bunsen. A,B,C and D respectively are:

When a substance A reacts with water, it produces a combustible gas B

1.	When a substance A reacts with water, it produces a combustible gas B and s solution of substance C in water. When another substance D reacts with this solution of C, it produces the same gas B on warming but D can produces gas B on reaction with dilute sulphuric acid at room temperature . A imparts a deep golden yellow colour to a smokeless flame of Bunsen. A,B,C and D respectively are:
Answer» `NA,H_(2),NAOH, Zn` `K, H_(2),KOH, Al` `Ca,H_(2), Ca(OH)_(2), Sn` `CaC_(2), C_(2)H_(2),Ca(OH)_(2),Fe` Solution :`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.