Question

When a graph is drawn between the pressure and temperature of the gas it is known as _________

(a) isochoric

(b) isobar

(c) isotherm

(d) isotopic

I got this question by my college director while I was bunking the class.

Enquiry is from States of Matter topic in section States of Matter of Chemistry – Class 11

Answer 1

The correct answer is (b) isobar.

Explanation:

When a graph is drawn between the pressure and temperature of a gas at constant pressure, it is known as an isobaric process. In such a process, the pressure remains constant while the temperature and volume of the gas change, according to Charles's Law.

• Isochoric (Option a): Refers to a process where the volume of the gas remains constant.
• Isobar (Option b): Refers to a process where the pressure remains constant.
• Isotherm (Option c): Refers to a process where the temperature remains constant. This would be a graph between pressure and volume, not pressure and temperature.
• Isotopic (Option d): Refers to the study of isotopes, which are atoms of the same element with different numbers of neutrons. This term does not apply to the gas law context.

So, when plotting a graph of pressure vs. temperature at constant pressure, the process is isobaric.