# Most stable cation

I am facing difficulty in the following problem:

Which of the following cations is the most stable?

If we take the number of hyper conjugative structures into consideration then a) should be most stable. It is known that $\ce{-OH}$ is a $\ce{-I}$ group. So if it is present nearer to the carbonation it must destabilise it.Near the carbonation $\ce{-I}$ effect should be more effective than $\ce{+M}$ effect. However my textbook gives the answer as c). Is there something that I am missing out? Thanks.

• @aniline think about the lone pairs on the oxygen atom and how they can contribute – getafix Dec 25 '16 at 22:38
• @getafix Yes it's true that $OH$ group will also exert $+M$ effect.But since it is very close to the carbonation its inductive effect should dominate over the mesomeric effect.Moreover mesomeric effect should be neglected since it will bring about a positive charge on more electronegative oxygen. – Pink Dec 26 '16 at 1:28
• That's what make (c) more stable – getafix Dec 26 '16 at 1:30
• @getafix I couldn't follow.as I have pointed out in the comment above how can be judge that in a fight between inductive and mesomeric effect how can we say that mesomeric effect will win when it has a destabilising effect as well. – Pink Dec 26 '16 at 1:44
• What does a carbocation look like? How is the p orbital positioned. How are the lone pairs on oxygen atom positioned? Can electrons transfer from oxygen to the vacant p orbital ? How does the inductive effect work? Think about these questions. I'm afraid I cannot write up a complete explanation right now – getafix Dec 26 '16 at 1:48