Question

What happens when phenol is oxidised with $Na_2Cr_2O_7$/ $H^{+}$? Write a chemical equation in support of your answer.

Answer 1

Hint: This reaction represents the chemical property of phenol which will lead to the formation of hydroquinone. We can say that it is a two-step reaction. So, we can identify the happening in the oxidation of phenol.

Complete step by step answer:

Now, as mentioned we know this reaction will occur in two-step.

In the first step, there will be oxidation of phenol with an acidified solution of sodium dichromate. The acidified solution means that there is presence of an acid like sulphuric acid.

The chemical reaction is

Now, in the reaction we can see the product formed is benzoquinone, that is a conjugated diketone.

We can say that the whole reaction ,occurring in two steps, is an example of phenol oxidation reaction.

In the last we can say that when phenol is oxidised to sodium dichromate in acidified solution, it will form benzoquinone.

The reactions have been represented in the support of the answer.

Additional Information: 

As phenols are oxidised in the presence of air, to the quinone; i.e. the dark-coloured mixtures. So, the reaction of phenols should be performed with attention.

Note:

It should be noted the above reaction is a two-step process. In the second step, there is hydrolysis of benzoquinone, the chemical reaction is

Here, we can see that there is formation of hydro-quinones in the later stage.