Consider a mixture of n moles of helium gas and 2n moles of oxygen gas (molecules taken to be rigid) as an ideal gas. Its $C_{P} / C_{V}$ value will be :

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

19/13

23/15

67/45

40/27

answer is C.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

$\begin{array}{l} F o r H e l i u m (m o n o a t o m i c g a s) c_{v_{1}} = \frac{3}{2} R a n d c_{p_{1}} = \frac{5}{2} R H e r e n_{1} = n \\ F o r o x y g e n (d i a t o m i c g a s) c_{v_{2}} = \frac{5}{2} R a n d c_{p_{2}} = \frac{7}{2} R H e r e n_{2} = 2 n \\ γ_{m i x} = \frac{n_{1} c_{p_{1}} + n_{2} c_{p_{2}}}{n_{1} c_{v_{1}} + n_{2} c_{v_{2}}} = \frac{n (\frac{5}{2} R) + 2 n (\frac{7}{2} R)}{n (\frac{3}{2} R) + 2 n (\frac{5}{2} R)} = \frac{5 + 14}{5 + 10} = \frac{19}{13} \end{array}$