Hello student,

The gas law is the law that relates the pressure (P), volume (V), and temperature (T) of  a gas. There are three primary gas laws (Charles' Law , Boyle's Law and Avogadro's Law ) of gas that combines into a General Gas equation or Ideal Gas Law.

Formula : PV = nRT

• P is the pressure of the ideal gas.
• V is the volume of the ideal gas.
• n is the amount of ideal gas measured in terms of moles.
• R is the universal gas constant .
• T is the temperature.

Proof :

Let us consider the pressure exerted by the gas to be ‘ p, ’

The volume of the gas be – ‘ v ’

Temperature be – T

n – be the number of moles of gas

Universal gas constant – R

According to Boyle’s Law ,

At constant n & T, the volume bears an inverse relation with the pressure exerted by a gas.

i.e. v∝1p ………………………………(i)

According to Charles’ Law,

When p & n are constant, the volume of a gas bears a direct relation with the Temperature.

i.e. v∝T ………………………………(ii)

According to Avogadro’s Law,

When p & T are constant, then the volume of a gas bears a direct relation with the number of moles of gas.

i.e. v∝n ………………………………(iii)

Combining all the three equations, we have-

v∝nTp

or pv=nRT

where R is the Universal gas constant , which has a value of 8.314 J/mol-K

All the best and thank you.