A student is provided with four unlabelled bottles containing different organic liquids. They perform test-tube reactions to identify them.
Which compound reduces acidified potassium dichromate(VI) from orange to green, but produces no observable change when warmed with Fehling's solution?
Propanal, CH3CH2CHO\text{CH}_3\text{CH}_2\text{CHO}CH3CH2CHO
Propan-2-ol, CH3CH(OH)CH3\text{CH}_3\text{CH(OH)CH}_3CH3CH(OH)CH3
Propanoic acid, CH3CH2COOH\text{CH}_3\text{CH}_2\text{COOH}CH3CH2COOH
2-Methylpropan-2-ol, (CH3)3COH(\text{CH}_3)_3\text{COH}(CH3)3COH