\(PV = \frac{M}{{{M_\omega }}}RT\,\,\,\therefore \,\,\,\,P \propto M \Rightarrow \frac{{{P_2}}}{{{P_1}}} = \frac{{{M_2}}}{{{M_1}}}\)
\(\frac{{2.5 \times {{10}^6}}}{{{{10}^7}}} = \frac{{M - {M^1}}}{M} = \frac{{10 - {M^1}}}{{10}}\)
\(\frac{{25}}{{100}} = \frac{{10 - {M^1}}}{{10}} \Rightarrow 20 - 2{M^1} = 5\, \Rightarrow \,15 = 2{M^1}\,\,\,\,{M^1} = 7.5\,\,kg\)
$\left(\right.\left.{k}_{{B}}=1.38 \times 10^{-23} \, {J} / {K}\right)$