Question

For independent processes at $300\, K$

Process	$\Delta H / kJ mol ^{-1}$	$\Delta S / JK ^{-1}$
A	-25	-80
B	-22	40
C	25	-50
D	22	20

The number of non-spontaneous processes from the following is

Answer 1

$ \Delta G =\Delta H - T \Delta S$
$A : \Delta G \left( J mol ^{-1}\right)=-25 \times 10^3+80 \times 300:- ve $
$ B : \Delta G \left( J mol ^{-1}\right)=-22 \times 10^3-40 \times 300:- ve$
$ C : \Delta G \left( J mol ^{-1}\right)=25 \times 10^3+300 \times 50:+ ve$
$ D : \Delta G \left( J mol ^{-1}\right)=22 \times 10^3-20 \times 300:+ ve$
Processes $C$ and $D$ are non-spontaneous.