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 is used to test for the presence of aldehydes and is not typically effective for distinguishing between ketones like acetone and benzophenone. Thus, this is not the correct answer.
Step 2: Tollen’s Reagent (Option 2) Tollen’s reagent is also used to test for aldehydes, and like Fehling's reagent, it is not used to distinguish between ketones. Therefore, this option is not correct.
Step 3: 2,4-DNP Reagent (Option 3) The 2,4-DNP reagent reacts with both aldehydes and ketones but forms a colored derivative, which is especially useful in distinguishing between different types of carbonyl compounds. In this case, it can differentiate between acetone (a simple ketone) and benzophenone (an aromatic ketone), making it the correct reagent to distinguish between the two.
Step 4: I\(_2\)/NaOH (Option 4) Iodine in NaOH is used in the iodoform test to detect compounds with a methyl ketone group. Neither acetone nor benzophenone would yield a reaction with I\(_2\)/NaOH.
Final Answer: \[ \boxed{\text{The correct reagent is 2,4-DNP reagent.}} \]