Discussion Forum

A closed vessel with rigid walls contains  1 mole of  $^{238}_{92}U$  and 1 mole of air at 298 K. considering complete  decay of  $^{238}_{92}U$ to $^{206}_{82}Pb$, the ratio of the final pressure to the initial pressure of the system at 298 K  is

Answer:

Explanation:

$_{92}U^{238}\rightarrow _{82}Pb^{206}+8 _{2}He^{4}(g)+6 _{-1}\beta^{0}$

n(gas) [Initial]=1 (air)

n(gas) [final]=8(He)+1(air)=9

$\Rightarrow$    At constant temperature and volume:  $p \propto n$ . 

 So,        $\frac{P_{f}}{P_{i}}=\frac{n_{f}}{n_{i}}=\frac{9}{1}=9$