Explanation:

• A mixture of acetylene gas and air is used.
• Anti-hail gun is a machine that generates shock waves to disrupt the growth of hailstones in clouds.

What are Hailstorms?

• A hailstorm is an unusual weather phenomenon in which balls of ice, called hail, fall from the sky. The ice balls are nothing more than solid precipitation that forms under certain conditions.

Hence only statement 2nd is correct.