Question

On the surface of the earth at 1 $atm$ pressure, a balloon filled with $H_2$ gas occupies 500 $mL$. This volume 5/6 of its maximum capacity. The balloon is left in air. It starts rising. The height above which the balloon will burst if temperature of the atmosphere remains constant and the pressure decreases 1 $mm$ for every 100 $cm$ rise of height is:

• A. 120 $mm$
• B. 136.67 $mm$
• C. 126.67 $mm$
• D. 100 $mm$

Answer 1

Answer: (C)

126.67 $mm$

From Ideal gas law equation:

$P_1$$V_1$ = $P_2$$V_2$

$1\times 500=P_2\times 600$

$P_2$ $=$ $\frac{5}{6}$ $atm$

$P_2=633.33mm$ of $Hg$

Pressure difference:

$\Rightarrow 760-633.33$

$\Rightarrow$ 126.67 $mm$