Methanol and ethanol are miscible in water due to

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?

$1 \ mol$ of alcohol reacts with $Na$ to produce what weight of hydrogen (in $g$)?

$R-OH + HX \to R-X + H_2O$. In the above reaction,the reactivity of different alcohols is:

The reaction shown below is an example of:
$CH_2=CH-COOCH_3 + CH_3CH_2CH_2OH \xrightarrow{\text{Conc. } HCl} CH_2=CH-COOCH_2CH_2CH_3 + CH_3OH$

$CH_3 CH_2 OH$ $\xrightarrow{Cl_2} CH_3 CHO$ $\xrightarrow{3 Cl_2} Cl_3 CCHO$. In the above reactions,the role of $Cl_2$ in step-$1$ and step-$2$ respectively is: