Two liters of `N_(2)` at `0^(@)C` and `5` atm pressure is expanded isothermally against a constant external pressure of `1` atm untill the pressure of gas reaches `1` atm. Assuming gas to be ideal, claculate the work of expansion.

Options

A. `-202. 6 J`
B. `-202. 6 J`
C. `-810.4 J`
D. `-303.9 J `

Answer

D

Explanation

Work is done against constant external pressure greatly different from the pressure `N_2` and thus process is ireversible.
`V_1 =2 `litre `V_2 =?`
`P_1 = 5 atm " " P_2 =2 atm`
`because P_1V_1 =P_2 V_2`
`because P_(ext) =1 xx 1.013 xx 10^5 Nm^(-2)`
`Delta V_2 C_1 =(5 -2) " litre " = 3xx 10^(-3) m^(3)`
`therefore W =- P_("ext")(V_2 -V_1)=- xx 1.013 xx 10^5 xx 3 xx 10^(-3) m^(3)`
-303. 89 J