Suggest the reagent for conversion of ethanol to ethanoic acid.

Explain the dehydration reaction of $2$-methylbutan-$1$-ol with concentrated $H_2SO_4$.

Identify the product $B$ in the following series of reactions.
$CH_3-CH_2-CH_2-OH$ $\xrightarrow{Al_2 O_3, 623 \ K} A$ $\xrightarrow[(ii) H_2 O]{(i) \text{conc. } H_2 SO_4} B$

In the following sequence of reactions,the compound $C$ formed will be:
$CH_3-CH(NH_2)-CH_3$ $\xrightarrow{HNO_2} A$ $\xrightarrow{\text{Oxidation}} B$ $\xrightarrow[(ii) H^+/H_2O]{(i) CH_3MgI} C$

An organic compound $X$ on treatment with $PCC$ in dichloromethane gives the compound $Y$. Compound $Y$ reacts with $I_{2}$ and alkali to form a yellow precipitate of triiodomethane. The compound $X$ is

Which of the following is the most suitable reagent for the conversion of $RCH_2OH$ to $RCHO$?