Glycerol reacts with potassium bisulphate to produce

$A$ substance $C_4H_{10}O$ yields on oxidation a compound $C_4H_8O$ which gives an oxime and a positive iodoform test. The original substance on treatment with conc. $H_2SO_4$ gives $C_4H_8$. The structure of the compound is:

In glycerol,which of the following is true regarding the $-OH$ groups?

$X + HCl$ $\xrightarrow[\text{Addition}]{\text{Anhy. } AlCl_3} C_2H_5Cl \xleftarrow[\text{Substitution}]{\text{Anhy. } ZnCl_2/HCl} Y$. The conversion of $Y$ to $X$ can be achieved by heating with .......... at .......... temperature.

Which of the following compounds is more acidic?

Ethyl alcohol on heating with conc. $H_2SO_4$ gives