What is ethanol containing a small amount of methanol called?

In the esterification reaction of $p$-toluic acid with methanol $(CH_3^{18}OH)$,the product $A$ is:

Primary and secondary alcohols on action of reduced copper give

An alcohol $X$ $(C_4H_{10}O)$ does not give turbidity with conc. $HCl$ and $ZnCl_2$ at room temperature. $X$ on reaction with reagent $Y$ gives $Z$. What are $X, Y$ and $Z$ respectively?

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

Which of the following is the correct decreasing order of reactivity for acid-catalyzed esterification of alcohols?