Question

1 mole of H2 gas is contained in a box of volume

V = 1.00 m3 at T = 300 K. The gas is heated to a temperature of T = 3000 K and the gas gets converted to a gas of hydrogen atoms. The final pressure would be (considering all gases to be ideal)

• A. Same as the pressure initially
• B. 2 time the pressure initially
• C. 10 times the pressure initially
• D. 20 times the pressure initially

Answer 1

Answer: (D)

20 times the pressure initially

Answer 2

According to gas equations PV = Nrt

or $\frac{P_{2}V_{2}}{T_{2}} = \frac{P_{1}V_{1}}{T_{1}}or\frac{P_{2}}{P_{1}} = \frac{V_{1}}{V_{2}},\frac{T_{2}}{T_{1}}$

Here, $T_{2} = 3000K,T_{1} = 300K$

Since $H_{2}$splits into hydrogen atoms, therefore volume becomes half i.e.,

$V_{2} = \frac{1}{2}V_{1}$

$\therefore\frac{P_{2}}{P_{1}} = \frac{V_{1}}{\frac{1}{2}V_{1}} \times \frac{3000}{300}$

or $\frac{P_{2}}{P_{1}} = 20$