product of reaction.

Aromaticity brings a greater deal of stability than tautomerism. That is why phenols do not tautomerise.

thnx to all for explaining....

I think YG files is wrong then..
becoz when it comes to assertion reason..they should ask only major product....
becoz if we start considering minor products..then there wont be just 2..there would be 1000 more products..based on probablity of reactants colliding...

it is formed no doubt but its percentage is very less.

This is because tautomerism is a case of equilibrium so either form will exist in some quantity.

The major one will of course be the aromatic product

this was a question in the Brilliant YG File question book.
It was an assertion-reason question.
Statement 1- when phenol is treated with nitrous acid, p-benzoquinone mono oxime ( product shown by iota), is formed.

this statement 1 is given as true. so i was confused.
plz someone confirm the mechanism.

The statement 2 of this question was false so i've not given it.

So it will NOT tautomerise[4]

Don't worry, even at FIITJEE most of the faculty is dumb and they will give the wrong answers to questions in phase tests at the expense of whether the student will get the proper knowledge or not. Our chem teacher(who has had many run-ins with the faculty) told us so. He has never lied to us.
Don't lose heart because they gave you negative marks. You know whether you're right or wrong.

ya i checked a book..stop at step1..only -NO is introduced.

yes iota,,check it once.

iota, why would it tautomerise and lose its aromaticity?
And for the mechanism, add a proton to OH in HO-N=O, water will leave and the nitrosonium ion(N⁺=O) will attack the benzene ring.