Question

2 mole of an ideal gas at ${27}^{0}C$ expands isothermally and reversibly from a volume of 4 litre to 40 litre. The work done ( in kJ) by the gas is :

• A. W = -28.72 kJ
• B. W = -11.488 kJ
• C. W = -5.726 kJ
• D. W = -4.988 kJ

Answer 1

The correct option is B W = -11.488 kJ

$n=2,T=27+273=300K,V_2=40L,V_1=4L$

Work Done, $W=-2.303nRT\log \left(\frac{V_2}{V_1}\right)$

$=-2.303\times 2\times 8.314\times 300\times log\left(\frac{40}{4}\right)$

$=-11.488kJ$