In the reaction,

The structure of the product T is :

One mole of an ideal gas is taken from $\mathbf{a}$ to $\mathbf{b}$ along two paths denoted by the solid and the dashed lines as shown in the graph below. If the work done along the solid line path is $W_{\text {s }}$ and that dotted line path is $W_{\mathrm{d}}$, then the integer closest to the ratio $W_{\mathrm{d}} / W_{\mathrm{s}}$ is

Total number of geometrical isomers for the complex $\left[\mathrm{RhCl}(\mathrm{CO})\left(\mathrm{PPh}_3\right)\left(\mathrm{NH}_3\right)\right]$ is ___________.

Two aliphatic aldehydes $\mathbf{P}$ and $\mathbf{Q}$ react in the presence of aqueous $\mathrm{K}_2 \mathrm{CO}_3$ to give compound $\mathbf{R}$, which upon treatment with HCN provides compound $\mathbf{S}$. On acidification and heating, $\mathbf{S}$ gives the product shown below :

The compounds P and Q respectively are :