a certain arene C8H10 is oxidized by potassium dichromate to benzoic acid, C6H5COOH. What is this arene?

a. o-xylene
b. m-xylene
c. P-xylene
d. ethylbenzene

I would go with d.

To determine which arene is oxidized to benzoic acid, we need to compare the chemical structures of the given options with that of benzoic acid (C6H5COOH).

The molecular formula of benzoic acid is C7H6O2, and it consists of a benzene ring (C6H6) with a carboxylic acid functional group (COOH) attached to it.

Let's analyze each option:

a. o-xylene: The molecular formula of o-xylene is C8H10. It contains two methyl groups (-CH3) attached to a benzene ring. This structure does not match the molecular formula of benzoic acid, so it is not the correct answer.

b. m-xylene: The molecular formula of m-xylene is also C8H10. Similar to o-xylene, it consists of two methyl groups attached to a benzene ring. This structure does not match the molecular formula of benzoic acid, so it is not the correct answer.

c. p-xylene: The molecular formula of p-xylene is C8H10. Like o-xylene and m-xylene, it has two methyl groups attached to a benzene ring. Again, this structure does not match the molecular formula of benzoic acid, so it is not the correct answer.

d. ethylbenzene: The molecular formula of ethylbenzene is C8H10. It consists of an ethyl group (-CH2CH3) attached to a benzene ring. This structure does not match the molecular formula of benzoic acid, so it is also not the correct answer.

Since none of the given options match the molecular formula of benzoic acid (C6H5COOH), none of the options represent the arene that is oxidized to benzoic acid.

Therefore, the correct answer cannot be determined from the given options.