Question

A metal on reaction with a dilute acid liberates gas which burns with a pop sound.

• A. hydrogen
• B. oxygen
• C. carbon dioxide
• D. carbon monoxide

Answer 1

The correct option is A hydrogen

Metals on reaction with acids produces salt and hydrogen gas.
For example, $2\mathrm{Na}\left(s\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to H_2\left(g\right)+2\mathrm{NaCl}\left(\mathrm{aq}\right)$
The hydrogen gas burns with a characteristic pop sound.