Question

Choose the correct statement:

• A. Hydrogen gas is collected by downward displacement of water.
• B. Hydrogen gas is collected by downward displacement of air.
• C. Hydrogen gas is collected by upward displacement of water.
• D. Hydrogen gas is collected by upward displacement of air.

Answer 1

The correct option is A

Hydrogen gas is collected by downward displacement of water.

Gases are collected by inverting a water-filled tube placed over the exit point of the gas, in a water trough. As the gas enters the collecting tube it pushes the water into the tube, down and out. This method is known as the downward displacement of water method of collecting gases and hydrogen is collected by this method because it is less dense and insoluble in water.