Which of the following is used to convert olefins into aldehydes?

What is the major product of the following reaction? $CH_3-C \equiv N$ $\xrightarrow[Et_2O]{CH_3MgI}$ $\xrightarrow{H_3O^{+}}$

Acetophenone is prepared by the reaction of which of the following in the presence of $AlCl_3$ catalyst?

Give the conversion of the following:
$(i)$ Lactic acid from ethanal
$(ii)$ $p-$fluorobenzaldehyde from $p-$fluorotoluene

Which of the following reactions will produce $R-CO-Ar$?

In column - $I$ reaction name,in column - $II$ reactant and in column - $III$ product are given,match column - $I$ with column - $II$ and column - $III$ with the correct option.

Column - $I$ and $II$	Column - $III$
$(A).$ Rosenmund reaction - $(i).$ $H_2, Pd, BaSO_4$	$(p).$ Benzene to benzaldehyde
$(B).$ Stephen reaction - $(iii).$ $SnCl_2, HCl$	$(q).$ Benzoyl chloride to benzaldehyde
$(C).$ Etard reaction - $(iv).$ $CrO_2Cl_2, CS_2$	$(r).$ Toluene to chromium complex
$(D).$ Gatterman-Koch reaction - $(ii).$ $CO, HCl$ anhydrous $AlCl_3/CuCl$	$(s).$ $RCN \to RCHO$