Assertion (A): According to gas equation,

$\dfrac{\text{P}$1\text{V}1}{\text{T}1} = $\dfrac{\text{P}2\text{V}$2}{\text{T}2}

Reason (R): On combining Boyle's law and Charle's law, 'volume of a given mass of a dry gas varies inversely as the pressure and directly as the absolute temperature."

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Both A and R are true and R is the correct explanation of A.

Explanation — On combining Boyle's law and Charle's law we conclude that 'volume of a given mass of a dry gas varies inversely as the pressure and directly as the absolute temperature'.

V=$\dfrac{T}{P}$ × constant

or $\dfrac{PV}{T}$ = K (constant)

If the volume of a given mass of a gas changes from V₁ to V₂ pressure from P₁ to P₂ and temperature from T₁ to T₂ then,

$\dfrac{\text{P}$1\text{V}1}{\text{T}1} = $\dfrac{\text{P}2\text{V}$2}{\text{T}2} =K (constant) ⟶ Gas Equation

Hence Both assertion(A) and reason(R) are true and R is the correct explanation of A.