Consider the processes in $\textbf{Group – 1}$ and the reactions in $\textbf{Group – 2}$.

$\begin{array}{llll} & \textbf{Group – 1} & & \textbf{Group – 2} \\ \textbf{P} & \text{Solvay process} & \textbf{I} & RCOOH + NaOH \rightarrow RCOONa + H_2O \\ \textbf{Q} & \text{Oxo process} & \textbf{II} & CH_2 = CH_2 + CO + H_2 \rightarrow CH_3CH_2CHO \\ \textbf{R} & \text{Saponification} & \textbf{III} & CaCO_3+2NaCl \rightarrow Na_2CO_3+CaCl_2 \end{array}$

The correct combination is

1. $P-II, Q-I, R-III$
2. $P-III, Q-II, R-I$
3. $P-III, Q-I, R-II$
4. $P-I, Q-III, R-II$