Doubt from dehydration of alcohol


@Shaquib Sir i am confused . Isn't it rate of dehydration depend upon stability of carbocation (+H effect)

1 Like

As far as i remember, the rate should be proportional to the stability of C+ and hence order should should have been
2>3>1>4>5 :thinking: but it doesn’t match with either options :face_with_monocle:

1 Like

In solution they have given rate is proportional to more subsituted alkene. They are comparing rate due to stability of product. I am fully confused

4th aur 1st ko aache se dekh 4th me hi c+ jyada stable hai 4th mein alpha h 5 hai

See rate is directly proportional to stability of carbocation

1 Like

That means there is some fault with question ?

Yeah I think

1 Like

I found another source of this question
Play Video Solution :play_or_pause_button: : :point_right: https://doubtnut.app.link/dJK7fISGT1
@Shaquib Sir pls review it.

See concept is same rate will be directly proportional to stability of carbocation
But in this question there is two 3 degree carbocation
Two 2 degree carbocation
And one 1 degree
So we have decide among them as stable pie bond.

I the above video they told about comparing stability of alkene in case of 3degree C+ but why will we do so?
As far as i know Stability of alkene doesn’t effect the rate of dehydration, among 3 degree C+ also number of alpha hydrogen are different, we can compare the rate using it.

1 Like

You are not getting my point
I am saying if there is more than one 3 degree carbocation then we will go for stability of pie bond which is actually number of alpha hydrogen.

It’s not necessary that apha H of alkene and C+ will give the same order , both are completely different
For example

Both are 3 degree and if we will compare acc to alpha H of C+ and acc to alpha H of alkene then both the orders will be different