The most stable carbocation amongst the following is:
→ Bridge head carbocation is highly unstable
Reason, the bridge head carbocation unable to acquires the planarity [120o] , and hence it is highly unstable.
As the no. of +IE groups [alkyl groups] increases,
sharing of positive charge by no of carbon atoms increases,
i.e., charge distribution among the atoms increases,
hence stability of carbocation increases.
"H" is neither +IE nor –IE group Here "CH3" group acts as +IE group
+ve cahrge located only on single carbon
+ve charge is shared among the 4-carbon atoms