CrO₃ in H₂SO₄/H₂O will fail to give a positive test with which of these compounds?

Question

Quizplus · Accepted Answer

The question is asking which compound(s) will fail to give a positive test with the given reagent, cromic acid (CrO3 + H2SO4). This reagent is used to oxidize aldehydes and primary alcohols to carboxylic acids. 
Choice A contains four hydroxyl groups, which are all primary alcohols and will be oxidized to carboxylic acids by cromic acid, giving a positive test. 
Choice B and D are not chemical compounds and therefore cannot be tested with cromic acid. 
Choice E cannot be determined solely from the information given. 
Choice C contains only one primary alcohol, which will give a positive test with cromic acid. However, the presence of the thioether group may interfere with the reaction, leading to a false negative result. Therefore, choice C is the best answer.

CrO3 in H2SO4/H2O Will Fail to Give a Positive Test

CrO₃ in H₂SO₄/H₂O Will Fail to Give a Positive Test