Which of the following is most reactive toward $S_{N}2$ reaction?

The major product of the following reaction is $CH_3-CH(CH_3)-CH(Br)-CH_3 \xrightarrow{CH_3OH}$

What will be the reduction products of the following reactions:
$CHCl_3 \xrightarrow[Zn/HCl \text{ (alc.)}]{+2H}$
$CHCl_3 \xrightarrow[Zn/HCl \text{ (aq.)}]{+4H}$
$CHCl_3 \xrightarrow[Zn/H_2O]{+6H}$

What are ambident nucleophiles? Explain with an example.

Identify the correct reactivity order for $S_N1$ reaction for the following compounds:

Given below are two statements:
Statement $(I)$: Benzyl chloride reacts faster in $S_N1$ mechanism than ethyl chloride.
Statement $(II)$: Ethyl carbocation intermediate is less stabilized by hyperconjugation than benzyl carbocation by resonance.
In the light of the above statements, choose the correct answer from the options given below: