List of top Chemistry Questions on Acids and Bases asked in JEECUP

Which gas is liberated when an acid reacts with a metal? 

Equivalent weight of a dibasic acid is 12. Its molecular weight is:
Accepting the definition that an acid is a proton donor, the acid in the following reaction
\[ NH_3 + H_2O \rightleftharpoons NH_4^+ + OH^- \] is