$PCl_5$ reacts with propanone to give:

$Ph-CH_3$ $\xrightarrow{CrO_2Cl_2} (A)$ $\xrightarrow{conc. KOH} Ph-CH_2OH + (B)$
Product $(B)$ of the above reaction is:

Both ethanal and propanone will react with which of the following?

In the following reaction,'$A$' is

The major product of the following reaction sequence is

In the following reaction:
$\text{Aldehyde} + \text{Alcohol} \xrightarrow{HCl} \text{Acetal}$
$HCHO \qquad ^tBuOH$
$CH_3CHO \qquad MeOH$
The best combination for the formation of acetal is: