Methanol and ethanol are distinguished by the

$Ph-CH_2-CH(OH)-CH_3$ $\xrightarrow{K}$ $\xrightarrow{C_2H_5Br} (A)$. Product $(A)$ in the above reaction is:

Which of the following processes is best suited to distinguish between $1-propanol$ and $2-propanol$?

$CH_3MgBr + \text{Cyclopentanone}$ $\xrightarrow{H_3O^{+}} A$ $\xrightarrow{HBr} B$ $\xrightarrow{Mg/\text{ether}} C$ $\xrightarrow{HCHO}_{H_3O^{+}} D$ $\xrightarrow{HI} E$
$E$ is

In the given pairs of alcohols,in which pair is the second alcohol more reactive than the first towards hydrogen bromide $(HBr)$?

The conversion of ethyl alcohol to acetaldehyde is an example of what?