4.0 g of a gas occupies 22.4 litres at NTP. The specific heat capacity of the gas at constant volume is 5.0 JK^–1 mol–1. If the speed of sound in this gas at NTP is 952 ms^–1, then the heat capacity at constant pressure is : 

8.0 J K^-1 mol^-1

Speed of sound : v = \(\sqrt{\frac{\gamma RT}{M}}\)

$\gamma = \frac{M}{RT}v^2$

$C_P = \frac{\gamma R}{\gamma -1} = \frac{Mv^2}{T (\gamma -1) }$

As \(\gamma = \frac{C_P}{C_V}\), 

v = 952 m/s ; C_V = 5.0 JK^-1 ; M = 4.0 g

C_P = 8.0 J K^-1 mol^-1