Elimination of bromine from $2-$bromobutane results in the formation of

Consider the following bromides.
The correct order of $S_N1$ reactivity is

The optically inactive compound from the following is

Which among the following alkyl halides gives more than one product upon dehydrohalogenation?

Which of the following compounds will form a precipitate most readily with $AgNO_3$?

In the following reactions,
$(i) CH_3-CH(CH_3)-CH(OH)-CH_3 \xrightarrow{H^{+}/\text{heat}} A \text{ [Major product]} + B \text{ [Minor product]}$
$(ii) A$ $\xrightarrow[\text{in absence of peroxide}]{HBr, \text{dark}} C \text{ [Major product]} + D \text{ [Minor product]}$
the major products $(A)$ and $(C)$ are respectively: