Hydrogen gas is identified by which sound?

Correct answer: Pop sound

Hydrogen is a combustible gas, so it can burn rapidly when mixed with air. In the standard laboratory test, a burning splint is brought near the mouth of the container; hydrogen ignites with a characteristic ‘pop’ sound. Hence option A is correct. A whistling, rattling, or ordinary blast sound is not the accepted identification test. The test should be performed carefully because hydrogen-air mixtures may ignite suddenly.