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

In which alkyl halide,$SN^2$ mechanism is favoured maximum?

The correct sequence of bond enthalpy of $C-X$ bond is:

What is the product of the following reaction?

The correct description of the product in the following reaction is:
$CH_3-CH(Br)-CH_2OCH_3 \text{ } ((R)) \xrightarrow{NaCN, \text{acetone}} CH_3-CH(CN)-CH_2OCH_3$

Find the reactants which on heating with alcoholic $KOH$ produce the compound $CH_3-CH_2-CH_2-CH=CH_2$.
$(i) \ CH_3-CH(Br)-CH_2-CH_2-CH_3$
$(ii) \ CH_3-CH_2-CH(Br)-CH_2-CH_3$
$(iii) \ CH_3-CH_2-CH_2-CH_2-CH_2Br$
$(iv) \ CH_3-CH_2-CH_2-CH(Br)-CH_3$