Question

Which group will show more -I effect ...

-COOH or COOR.......

Answer 1

Well no doubt esters (-COOR) have higher -I effect. Because of the R group.

If you hydrolyze it COOH will always dissociate as COO- but COOR mighy dissociate as

CO+ and OR-

COO- and R+

Thus the bond breaking maybe alkyl bond breaking or acyl bond breaking as per the reaction conditions.

COOR indeed increases the electron density.

R group or H will never give -I effect. Only COO- will give -I effect. In your question both the species formed are COO-.

When R is present this -I will be quenched a lot but when H it is not quenched as much so COOH will always tend to dissociate.