Which of the following is not correct about Grignard reagent?

Consider the following reactions:
$X + HCl \xrightarrow{\text{Anhydrous } AlCl_3} C_2H_5Cl$
$Y \xrightarrow{\text{Anhydrous } ZnCl_2 / HCl} C_2H_5Cl$
$Y$ can be converted to $X$ on heating with which of the following reagents?

The vapours of an alcohol $(X)$ are passed over $Cu$ heated at $300^{\circ} C$,where an alkene is formed as the product. The alcohol $(X)$ is expected to be $:-$

$HBr$ reacts fastest with

$X$ and $Y$ respectively are

The reaction involved in the oil of wintergreen test is salicylic acid + reagent $\xrightarrow[Conc. H_{2}SO_{4}]{\Delta}$ product. The product is treated with $Na_{2}CO_{3}$ solution. The missing reagent in the above reaction is