$C_2H_5MgI$ reacts with $HCHO$ to form the final product.

What is the major organic product of the following sequence of reactions?
$(CH_3)_2CHCH_2OH$ $\xrightarrow{PBr_3}$ $\xrightarrow{Mg}$ $\xrightarrow{C_2H_4O}$ $\xrightarrow{H_3O^+} ?$

In the following sequence of reactions,the compound $D$ is
$CH_3CH_2OH$ $\xrightarrow{P + I_2} A$ $\xrightarrow[{ether}]{Mg} B$ $\xrightarrow{HCHO} C$ $\xrightarrow{H_2O} D$

An alcohol,$X$ $(C_5H_{12}O)$ in the presence of $Cu / 573 \ K$ gives $Y$ $(C_5H_{10})$. The reactants required for the preparation of $X$ are

What are $X$ and $Y$ in the following reactions?
$CH_2O \xrightarrow[(ii) H_3O^+]{(i) X} CH_3(CH_2)_2CH_2OH$
$Y \xrightarrow[(ii) H_3O^+]{(i) C_2H_5MgBr} CH_3CH_2C(CH_3)_2OH$

Which of the following combinations can be used for the synthesis of isopropyl alcohol?