The compound which forms acetaldehyde when heated with dilute $NaOH$ is

Which of the following is most reactive toward $S_N2$ reaction?

Predict the product for the following reaction:
$\xrightarrow[\Delta]{alc. \ KOH}$ product

The reaction of $1-$chlorobutane with alcoholic potassium hydroxide $(KOH)$ yields .....................

Which one of the following compounds is inactive towards $S_N1$ reaction?

In the following reaction sequence,the correct structure$(s)$ of $X$ is (are)
$X$ $\xrightarrow[2) NaI, Me_2CO]{1) PBr_3, Et_2O}$ $\xrightarrow{3) NaN_3, HCONMe_2} \text{enantiomerically pure product}$