
In the process $2 \rightarrow 3, \Delta W_{2 \rightarrow 3}=0$
In the process $3 \rightarrow 1, \Delta Q_{3 \rightarrow 1}=0$
The complete process being cyclic, $\Delta U=0$
Hence $\Delta Q=\Delta W \Rightarrow \Delta Q_{1 \rightarrow 2}+\Delta Q_{2 \rightarrow 3}+\Delta Q_{3 \rightarrow 1}=\Delta W_{1 \rightarrow 2}+\Delta W_{2 \rightarrow 3}+\Delta W_{3 \rightarrow 1} \Rightarrow$
$\Delta Q_{2 \rightarrow 3}=\Delta W_{3 \rightarrow 1}=-40 J$
