Alcoholic potash is used to bring about

The reaction of $n$-propyl bromide with ethanolic potassium hydroxide $(KOH)$ produces ...... .

Which of the following compounds has the lowest boiling point?

For each of the following pairs of $E_2$ reactions,select the one that occurs with the greater rate constant:
$(1)$ $CH_3-CH_2-CH_2-Cl + CH_3-C(CH_3)_2-O^-$
$(2)$ $CH_3-CH_2-CH_2-I + CH_3-C(CH_3)_2-O^-$
$(3)$ $CH_3-CH(Br)-CH_3 + CH_3-O^-$
$(4)$ $CH_3-CH(Br)-CH_3 + CH_3-S^-$
$(5)$ $Ph-CH_2-CH(Br)-CH_2-CH_3 + OH^-$
$(6)$ $Ph-CH_2-CH_2-CH(Br)-CH_3 + OH^-$

In the following reaction,the product $(Y)$ will be:

In $S_{N}2$ reaction,the carbon in the transition state is