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

In the reaction $C_6H_6 + CO + HCl \xrightarrow{A} C_6H_5CHO + HCl$,what is $A$?

Write a note on the preparation of primary alcohol from aldehyde by reduction reaction.

Give names of the reagents to bring about the following transformations:
$(i)$ $\text{Hexan-}1\text{-ol}$ to $\text{hexanal}$
$(ii)$ $\text{Cyclohexanol}$ to $\text{cyclohexanone}$
$(iii)$ $p\text{-Fluorotoluene}$ to $p\text{-fluorobenzaldehyde}$
$(iv)$ $\text{Ethanenitrile}$ to $\text{ethanal}$
$(v)$ $\text{Allyl alcohol}$ to $\text{propenal}$
$(vi)$ $\text{But-}2\text{-ene}$ to $\text{ethanal}$

$A$ man has been asked to synthesize the molecule shown in the image. He thought of preparing the molecule using an aldol condensation reaction. He found a few cyclic alkenes in his laboratory. He thought of performing an ozonolysis reaction on an alkene to produce a dicarbonyl compound,followed by an aldol reaction to prepare "$x$". Predict the suitable alkene that can lead to the formation of "$x$".

Which of the following reactions cannot be used to prepare Benzaldehyde?