Question

If the discharge tube is filled up with various gases in turn will the discharge in all gases take place at the same electrode potential?

Answer 1

Hint: In this question we will use the concept of discharge of gas in a discharge tube. Discharge tubes are used to explore the electrical conduction of gases at low pressure.

Complete step by step solution:
The discharge of a gas depends on two factors: Pressure of the discharge tube and ionisation potential of the gas. If we keep the pressure of the discharge tube constant and change the gases, the electrode potential won’t be the same as the ionisation potential of different gases will be different.

Hence, the correct answer is D.

Additional Information: If an electric current flows through a gas, it is known as electrical conduction or discharge in gas. At normal temperature and pressure, the gases are good insulators of electricity. We can make a gas conducting by applying very high voltage or reducing its pressure to a very low value.

The amount of energy required to remove an electron from a neutral atom is known as the ionisation energy or ionisation potential. For alkali metals with a single electron outside of a closed shell, it is a minimum. For the noble gases with closed shells, the periodic maximum typically increases across a row.

Note: Different elements have different ionisation potential which depends on many factors. For the same gas if we change pressure, the electrode potential will change and similarly, keeping the pressure same if we change the gases, the ionisation potential will change. Hence, the electrode potential will change.