Question

Which of the compounds bearing different nucleophile (Y) in (a)-(d) gives the terminal/internal alkene most readily in the following reaction?

• A. $Y=F$
• B. $Y=Cl$
• C. $Y=Br$
• D. $Y=I$

Answer 1

The correct option is D $Y=I$

Good leaving group favours E2 reaction
Increasing order of preference of leaving groups is
$F^{-}<C{l}^{-}<B{r}^{-}<I^{-}$ thus iodide ion as leaving group gives the terminal/internal alkene most readily.