Question

Which reagent will distinguish Benzophenone from acetone?

• A. Fehling’s reagent
• B. Tollen’s reagent
• C. 2,4-DNP reagent
• D. I\(_2\)/NaOH

Hint:

The 2,4-DNP reagent is useful for identifying carbonyl compounds by the formation of a colored derivative.

Answer 1

The Correct Option is C

Step 1: Fehling’s Reagent (Option 1) Fehling's reagent tests for aldehydes but does not distinguish between ketones like acetone and benzophenone. This option is incorrect.
Step 2: Tollen’s Reagent (Option 2) Tollen’s reagent also tests for aldehydes and cannot distinguish between ketones. Thus, this option is incorrect.
Step 3: 2,4-DNP Reagent (Option 3) 2,4-DNP reagent reacts with both aldehydes and ketones, forming colored derivatives that aid in distinguishing carbonyl compounds. It can differentiate between acetone (a simple ketone) and benzophenone (an aromatic ketone), making it the correct reagent.
Step 4: I\(_2\)/NaOH (Option 4) Iodine in NaOH is used for the iodoform test, which detects methyl ketone groups. Neither acetone nor benzophenone will react with I\(_2\)/NaOH.
Final Answer: \[\boxed{\text{The correct reagent is 2,4-DNP reagent.}}\]