Question

Which compound reacts with acidic dichromate (Cr2O72- / H+) to give the product shown?

The answer is C, but I don't understand that why it is not D.

Answer 1

It's not the same compund

Explanation:

Yeah, they are isomers ( they have the same molecular formula ) but:

oxidation of C) leads to 2-methyl propanoic acid ( the one on the right in the picture )
oxidation of D) leads to butyric acid
Those are also catene isomers

! it's not the same thing

Answer 2

Compound C reacts to give the product shown.

Explanation:

Compound A

Acidified dichromate does not oxidize tert-butyl alcohol under normal conditions.

Compound B

Secondary alcohols form ketones on oxidation.

`"CH"_3"CH"_2"CH(OH)CH"_3stackrelcolor(blue)("Cr"_2"O"_7^"2-""/H"^"+"color(white)(mm))(→) underbrace("CH"_3"CH"_2"C(=O)CH"_3)_color(red)("butan-2-one")`

This is not the observed product.

Compound C

Primary alcohols form carboxylic acids on oxidation.

`("CH"_3)_2"CHCH"_2"OH" stackrelcolor(blue)("Cr"_2"O"_7^"2-""/H"^"+"color(white)(mm))(→) underbrace(("CH"_3)_2"CHC(=O)OH")_color(red)(2-"methylpropanoic acid")`

This is the observed product.

Compound D

`"CH"_3"CH"_2"CH"_2"CH"_2"OH" stackrelcolor(blue)("Cr"_2"O"_7^"2-""/H"^"+"color(white)(mm))(→) underbrace("CH"_3"CH"_2"CH"_2"C(=O)OH"top)_color(red)("butanoic acid")`

This is not the observed product.