How many aldol products are possible (excluding stereoisomers) for the following reaction?
$CH_3-CHO + CH_3-CH_2-CHO \xrightarrow{OH^-/H_2O}$

Match the following lists:

Which of the following is least reactive towards nucleophilic addition?

Consider the reactions and identify $A, X, Y$ and $Z$:
$X (C_2H_6O)$ $\xrightarrow{Cu, 573 \ K} A$ $\xrightarrow{[Ag(NH_3)_2]^+, ^-OH, \Delta} \text{Silver mirror}$
$A \xrightarrow{^-OH, \Delta} Y$
$A \xrightarrow{NH_2NHCONH_2} Z$

The reaction between an ester and an excess of Grignard reagent $(R'MgX)$ finally results in a:

The option$(s)$ with the correct sequence of reagents for the conversion of $P$ to $Q$ is(are):
$(A)$ $i$) Lindlar's catalyst,$H_2$; $ii$) $SnCl_2 / HCl$; $iii$) $NaBH_4$; $iv$) $H_3O^{+}$
$(B)$ $i$) Lindlar's catalyst,$H_2$; $ii$) $H_3O^{+}$; $iii$) $SnCl_2 / HCl$; $iv$) $NaBH_4$
$(C)$ $i$) $NaBH_4$; $ii$) $SnCl_2 / HCl$; $iii$) $H_3O^{+}$; $iv$) Lindlar's catalyst,$H_2$
$(D)$ $i$) Lindlar's catalyst,$H_2$; $ii$) $NaBH_4$; $iii$) $SnCl_2 / HCl$; $iv$) $H_3O^{+}$