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

Which of the following phrases are not correctly associated with $S_N1$ reaction?
$(1)$ Rearrangement is possible
$(2)$ Rate is affected by polarity of solvent
$(3)$ The strength of the nucleophile is important in determining rate
$(4)$ The reactivity series is tertiary $>$ secondary $>$ primary
$(5)$ Proceeds with complete inversion of configuration

Which among the following is $NOT$ a feature of $S_N1$ mechanisms?

Name the following reaction: $CH_3CH_2Cl + NaI \xrightarrow{\text{acetone}} CH_3CH_2I + NaCl$

The correct pair$(s)$ of the ambident nucleophiles is (are):
$(A)$ $AgCN / KCN$
$(B)$ $RCOOAg / RCOOK$
$(C)$ $AgNO_{2} / KNO_{2}$
$(D)$ $AgI / KI$

Sodium tertiary butoxide on reaction with methyl bromide produces the product $P$.
Sodium methoxide upon reaction with tertiary butyl bromide generates the product $Q$.
The products $P$ and $Q$ are