Question

In a reaction between a metal and an acid, why are bubbles formed?

• A. Formation of $H_2$ gas
• B. Formation of $O_2$ gas
• C. Formation of metal salt
• D. None of the above

Answer 1

Answer: (A)

Formation of $H_2$ gas

Certain metals on reaction with acids liberate hydrogen gas. This is the reason why bubbles are formed in the solution.

For example, the reaction of zinc with hydrochloric acid leads to the formation of zinc chloride and hydrogen gas is released in the form of bubbles.

$Zn+2HCl\to ZnC{l}_2+H_2$