Functional Group Tests -- Results?

Question

Chromic acid test would give a "positive" or a "negative" result for:

1)2-Butanol

2) delta-Pinene

3)1-Butanol

4) 2-Methyl-2-propanol

anyone has any idea?thank you

Answer 1

1) positive a 2º alcohol --> ketone
2) negative a terpene
3) positive a 1º alcohol --> aldehyde
4) negative a 3º alcohol

Answer 2

it will give a +ve result to (1) &(3). But to all else the result will be -ve.

[ 2-Butanol & 1-Butanol being primary & secondary alcohols respectively, gets oxidized to a ketone & an aldehyde]

Answer 3

The Chromic acid test works as shown below:

A positive oxidation reaction is indicated by disappearance of the orange color of the reagent and the formation of a green or blue-green precipitate or emulsion.
• 1o & 2o ROH, aliphatic RCHO give + test w/in 5s
• Aromatic RCHO gives + test w/in 30-45s.
• 3o alcohols & ketones produce no visible change in several minutes.
• Phenols, aromatic amines, and aromatic RCHO’s (having hydroxyl or amino groups) give dark precipitates

You should know which alcohols above are primary, secondary, and tertiary and then you can answer it yourself.