Predict the effect of increasing the percentage of `H_2 O` in acetone `-H_2 O` solvent mixture in :
(a) `SN^1` solvolysis of `Me_3 C - Br`
(b) `SN^2` reaction of `K1` and `EtC1`.
(c) Predict the relative yields of the product of `Me_3 CBr` in `80% EtOH` and `20 % H_2 O`.

Explanation

(a) Adding more `H_2 O` increases the polarity of solvent and the rate of `SN^1` reaction increases.
(b) In `SN^2`, on increasing the solvent polarity, the rate decreases because of better solvation of `I^(Ө)` (with a full negative charge) in the `G.S` through H-bonding with `H_2 O`.
(c)
Althrough there is much more `EtOH` than `H_2 O, H_2 O` solvates `R^(oplus)` much better. Hence, more alcohol is formed than ethers.