Question

In a 20 litre flask, 60 litres of $N_2$ at 760 mm, 32 litres of $H_2$ at 740 mm are mixed. The total pressure of the mixture at the same temperature is :

• A. 3740 mm
• B. 1120 mm
• C. 2442 mm
• D. 3464 mm

Answer 1

The correct option is D 3464 mm

The number of moles of nitrogen are, $\frac{PV}{RT}=\frac{760\times 60}{RT}=\frac{45600}{RT}$

The number of moles of hydrogen are, $\frac{PV}{RT}=\frac{740\times 32}{RT}=\frac{23680}{RT}$

The number of moles of mixture are, $\frac{45600}{RT}+\frac{23680}{RT}=\frac{69280}{RT}$

The total pressure of the mixture is, $\frac{nRT}{V}=\frac{69280}{RT}\times \frac{RT}{20}=3464$ mm