Question

The hydrocarbons that contain _____ group are called ketones.

• A. \( -CHO \)
• B. \( -OH \)
• C. \( -COOH \)
• D. \( -CO- \)

Hint:

Remember these important organic functional groups:
• \( -OH \rightarrow \) Alcohol
• \( -CHO \rightarrow \) Aldehyde
• \( -COOH \rightarrow \) Carboxylic acid
• \( -CO- \rightarrow \) Ketone

Answer 1

The Correct Option is D

Concept:
Organic compounds are classified based on the functional group present in them. A functional group is an atom or group of atoms responsible for the characteristic chemical properties of a compound. Important functional groups include:
• Aldehyde : \( -CHO \)
• Alcohol : \( -OH \)
• Carboxylic acid : \( -COOH \)
• Ketone : \( -CO- \) Ketones contain a carbonyl group placed between two carbon atoms: \[ R-CO-R' \] where \(R\) and \(R'\) are alkyl groups.

Step 1: Understand what a ketone is.
A ketone is an organic compound containing: \[ \boxed{-CO-} \] This is called the carbonyl group in ketones. Example: \[ CH_3COCH_3 \] This compound is called acetone or propanone.

Step 2: Analyze each option carefully.
Option (A): \( -CHO \)
This represents the aldehyde group. Example: \[ CH_3CHO \] Hence, incorrect. Option (B): \( -OH \)
This represents alcohols. Example: \[ C_2H_5OH \] Hence, incorrect. Option (C): \( -COOH \)
This represents carboxylic acids. Example: \[ CH_3COOH \] Hence, incorrect. Option (D): \( -CO- \)
This is the ketone functional group. Hence, this option is correct.

Step 3: Select the correct answer.
Therefore, ketones contain the: \[ \boxed{-CO-} \] group. Hence, \[ \boxed{(4)\ -CO-} \]