Question

A gas is a mixture of two parts by volume of hydrogen and one part by volume nitrogen. If the velocity of sound in hydrogen at $27^{\circ} C$ is given as $1330\, m / s$, find the ratio of velocity of sound in hydrogen at $27^{\circ} C$ to the gaseous mixture at $127^{\circ} C$.

Answer 1

$v_{\text {sound }} \propto \sqrt{\frac{T}{M}}$
$M_{\text {mix }}=\frac{2 \times 2+28}{3}=\frac{32}{3}$
$\therefore \frac{v_{\text {sound } / H _{2}}}{v_{\text {sound } / \text { mix }}}=\sqrt{\frac{300 \times 32}{2 \times 400 \times 3}}=2$