Functional Group Analysis (SBA AI Prep)

T is a white solid which easily dissolves in water to form a colourless solution. T is most likely:

• Phenol

• Glycine

• 2-propanol

• 2-pentene

Answer explanation

Due to zwitterion formation, amino acids can form ionic bonds and thus have properties of ionic substances, e.g. solid at room temperature and soluble in water. Glycine is an amino acid.

Phenol is only moderately soluble. 2-propanol and 2-pentene are not solids.

Sample T was added to water and stirred until no further changes. Use the observation shown to identify T.

• Alcohol

• Carboxylic acid

• Amine

• Alkene

Answer explanation

Alkanes and alkenes are non polar and do not dissolve in water.

The observation shown was obtained when sample J was added to water and resulting mixture tested with litmus. Which of the following inferences can be made?

J may be

• an alcohol or amine

• a carboxylic acid or alcohol

• an aldehyde, ketone or carboxylic acid

• a carboxylic acid or phenol

Fehlings/Benedicts solution was added to Sample M which was heated gently. Use observation shown to identify the correct inference.

• M is an NOT an aldehyde

• M is a carbonyl compound

• M is a ketone.

• M is an aldehyde

Answer explanation

An aldehyde would give turn the blue solution to aa green/yellow/brick red ppt.

We cannot say M is a ketone unless we had previously confirmed that it was a carbonyl compound.

Sample X gave the results shown. It is most likely

• propanal

• propanone

• ethanal

• phenol

Answer explanation

Positive silver mirror means an aldehyde, and a positive iodoform means it has structure shown and ethanal is the only aldehyde with that structure.

Sodium metal was added to sample P and effervescence occurred. Which of the following would be the best inference?

• P may be a carboxylic acid

• P may be a carboxylic acid, alcohol or phenol

• P may be a carboxylic acid or phenol

• P may be a carboxylic acid or aldehyde

Sodium carbonate was added to sample P and effervescence occurred. Which of the following would be the best inference?

• P may be a carboxylic acid

• P may be a carboxylic acid, alcohol or phenol

• P may be a carboxylic acid or phenol

• P may be a carboxylic acid or aldehyde

The observation shown was obtained when sample V was added to water and resulting mixture tested with litmus. Which of the following inferences can be made?

V may be

• alcohol or amine

• an amine

• an aldehyde, ketone

• amine or amide

Compound W turned purple acidified KMnO₄ colourless. Identify the best inference.

• W is an alkene or alcohol

• W is an alcohol

• W is a ketone

• W is an alkane or alcohol

Sample F slowly decolourises Br₂ solution in diffused sunlight. What is the best inference?

• F is an alkane

• F is an alkene

• F may be an alkane or alkene

• F may be an alcohol