Which of the follwing represents the decreasing order of `K_(a)` values ?

Options

A. `(ii)gt(i)gt(iii)gt(iv)`
B. `(ii)gt(iii)gt(i)gt(iv)`
C. `(i)gt(ii)gt(iii)gt(iv)`
D. `(ii)gt(iv)gt(i)gt(iii)`

Answer

a

Explanation

In a given structures -
After releasing `H^(+)` from (ii) group , it forms a more stable resonating structure of carboxylate ion . In case of (i), the anion formed after release of `H^(+)` is more stable due to presence of `e^(-)` withdrawing `NO_(2)` in benzene ring . In (iii) , phenoxide ion formed after release of `H^(+)` is more stable in comparison to acetylide ion of group (iv) which is formed after releasing `H^(+)` from from (iv) so acidic order or `K_(a)` is
`(ii)gt(i)gt(iii)gt(iv)`