Two heat proof containers of volumes 1L and 2L are connected by a tube.Keeping the valve attached to the tube closed,the 1st container is filled with nitrogen at `0^@C` and at 0.5 standard atmosphere pressure, and the 2nd container with argon at `100^@C` and 1.5 standard atmosphere pressure. The temperature of the gas mixture becomes `79^@C` when the valve is opened,find the pressure of the gas mixture.

Explanation

In the 1st container pressure of nitrogen `(p_1)`=0.5 standard atmosphere, volume `(V_1)`=1L,temperature `(T_1)=0+273=273K`,
and in the 2nd container pressure of argon `(p_2)=1.5` standard atmosphere , volume `(V_2)=3L` Temperature `(T_2)=100+273=373K`
When the valve let the pressure of the gas mixture be p, volume `V=4L` and temperature `T=273+79=352K`
As `(pV)/T=nR`.
We have `n_1R+n_2R=(n_1+n_2)R`
or, `(p_1V_1)/T_1+(p_2V_2)/T_2=(pV)/T`
or, `(0.5 times 1)/273+(1.5 times 3)/373=(p times 4)352`
or,`p/88=0.0018+0.0120`
`therefore p=0.0138 times 88=1.2144` standard atmosphere