A certain mass of gas expanded from ( 1L, 10 atm) to (4 L, 5 atm) against a constant external pressure of 1 atm. If initial temperature of gas is 300 K and the heat capacity of process is `50 J//^(@)C`. Then the enthalpy change during the process is :
(`1"L" "atm" underline ~ 100 J`)

Options

A. `Delta H = 15 kJ`
B. `Delta H = 15.7 kJ`
C. `Delta H = 14.4 kJ`
D. Delta H = 14.7 kJ`

Answer

B

Explanation

`(P_(1)V_(1))/(T_(1)) = (P_(2)V_(2))/(T_(2)) rArr T_(2) 600 K, q = C. Delta T = 15 KJ`
`w = P_("ext") Delta V = 1 (4 - 1) = 0.3KJ Delta U = 14.7 KJ`
`Delta H = 14.7 + (5 xx 4 - 10 xx 1) xx 100 xx 10^(-3) = 15.7 KJ`