1. Reaction (i): Rosenmund Reduction Acyl chlorides ($RCOCl$) are hydrogenated over a catalyst, palladium on barium sulphate ($Pd/BaSO_4$). This reaction is used exclusively for the preparation of aldehydes ($RCHO$). The catalyst is poisoned with sulphur or quinoline to prevent further reduction to primary alcohols. $RCOCl + H_2 \xrightarrow{Pd/BaSO_4} RCHO + HCl$

2. Reaction (ii): Stephen Reaction Nitriles ($RCN$) are reduced to imines with stannous chloride in the presence of hydrochloric acid ($SnCl_2 + HCl$), which on hydrolysis give the corresponding aldehyde ($RCHO$). $RCN + SnCl_2 + HCl \rightarrow RCH=NH \xrightarrow{H_3O^+} RCHO$

Thus, both products A and B are aldehydes ($RCHO$).