Which compound produces acetaldehyde upon heating with aqueous $KOH$?

When $tert$-butyl bromide is heated with silver fluoride,the major product obtained is:

Rank the following compounds in order of decreasing rate of solvolysis with aqueous ethanol (fastest $\to$ slowest):
$(1)$ $CH_2=C(CH_3)Br$
$(2)$ $1-bromo-1-methylcyclohexane$
$(3)$ $CH_3-CH(Br)-CH_2-CH(CH_3)_2$

Which is most reactive for $S_{N}2$ reaction?

Which compound has the highest reactivity towards $S_{N}1$ reaction?

Identify the major product formed in the following reaction: $3-$Bromo$-2-$methylpentane $\xrightarrow{Alc. KOH, \Delta}$ Major product