Two gas bulbs are connected by a thin tube. calculate the partial pressure of He after the connective valve is opened at a constant temperature of 27°C

$\mathrm{For} \mathrm{Helium}, \mathrm{pressure} \mathrm{and} \mathrm{volume} \mathrm{before} \mathrm{connect} \mathrm{with} \mathrm{Ne} \mathrm{gas}.$

${\mathrm{P}}_1 = 0 . 63 \mathrm{atm}$

${\mathrm{V}}_1=1.2\mathrm{L}$

Pressure of ‘He’ after the value is opened    ${\mathrm{P}}_2=?$

${\mathrm{V}}_2={\mathrm{V}}_{\mathrm{He}}+{\mathrm{V}}_{\mathrm{Ne}}$

$=1.2+3.4$

${\mathrm{V}}_2=4.6\mathrm{L}$

${\mathrm{P}}_1{\mathrm{V}}_1={\mathrm{P}}_2{\mathrm{V}}_2$

$\mathrm{Then} {\mathrm{P}}_2=\frac{{\mathrm{P}}_1{\mathrm{V}}_1}{{\mathrm{V}}_2}$

$=\frac{0.63\times 1.2}{4.6}$

$=0.164 \mathrm{atm}$