Question

Consider a collision between an oxygen molecule and a hydrogen molecule in a mixture of oxygen and hydrogen kept at room temperature. Which of the following are possible?

• A. The kinetic energy of both the molecules increase.
• B. The kinetic energy of both the molecules decrease.
• C. The kinetic energy of the oxygen molecule increases and that of the hydrogen molecule decreases.
• D. The kinetic energy of the hydrogen molecule increases and that of the oxygen molecule decreases.

Answer 1

Answer: (C), (D)

The correct options are
C The kinetic energy of the hydrogen molecule increases and that of the oxygen molecule decreases.
D The kinetic energy of the oxygen molecule increases and that of the hydrogen molecule decreases.

Assuming elastic collision between the oxygen and hydrogen molecules, kinetic energy will be conserved.
Increase in KE of oxygen and decrease in KE of hydrogen, keeping the total energy conserved is possible.
Increase in KE of hydrogen and decrease in KE of oxygen, keeping the total energy conserved is possible.
Since KE is conserved, both cannot increase or decrease.