Question

What happens when an affixed amount of oxygen gas is taken in a cylinder compressed at constant temperature?
(a) number of collisions of oxygen molecules at per unit area of the wall of the cylinder increase.
(b) oxygen ${{O}_{2}}$ gets converted into ozone ${{O}_{3}}$.
(c) Kinetic energy of the molecules of oxygen gas increases.

(A) a and c
(B) b and c
(C) c only
(D) a only

Answer 1

Hint: When the gas is compressed, its molecules also get compressed and hence their collisions increases and remember that if temperature is constant then the kinetic energy of the gas is also constant. Now answer the statement.

Complete Solution :
- Oxygen is a non -metal which belongs to the 16th group and 2nd period of the periodic table and consists of six electrons in its valence shell and has a strong tendency to gain the electrons to complete its octet and to acquire the stable electronic configuration of the nearest noble gas.
- Now coming to the statement:
(a) When a fixed amount of oxygen gas is taken in a cylinder at constant temperature is compressed, then molecules of oxygen are also compressed and hence, the collisions of the oxygen molecules per unit area increases on the walls of the cylinder.
So, this statement is correct.

(b) In this, there is just compression of the oxygen gas, not its conversion into the ozone molecule.
So, this statement is incorrect.

(c) Since, the gas is compressed at constant temperature so there is no change in the kinetic energy of the oxygen gas i.e. it neither increases or decreases.
So, this statement is also incorrect.
Hence, from above all the given statements only statement (a) is correct.
So, the correct answer is “Option D”.

Note: Kinetic energy is directly proportional to the temperature. As the temperature increases, velocity of the molecules of gas also increases and hence, the kinetic energy also increases and vice -versa. i.e. $K.E.=\dfrac{1}{2}m{{v}^{2}}\alpha \text{ }temperature$