Identify $A, B$ and $C$ in the following reaction:
$\text{Toluene} + A + B$ $\xrightarrow{273-283 \ K} C$ $\xrightarrow{H_3O^{\oplus}} \text{Benzaldehyde}$

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

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 $\text{ethanal}$

What is the name of the given reaction?
$C_6H_6 + CO + HCl \xrightarrow{Anhyd. AlCl_3} C_6H_5CHO$

The reagent used in Gatterman-Koch aldehyde synthesis is

What are $A$ and $B$ in the following reaction sequence?
$\text{Propionitrile} + A$ $\longrightarrow B$ $\xrightarrow{H_3O^{+}} \text{propiophenone}$