Question

PCC is:

• A. K₂Cr₂O₇ + Pyridine
• B. CrO₃ + CHCl₃
• C. CrO₃ + H₂SO₄
• D. A complex of chromium trioxide with pyridine + HCl

Hint:

PCC oxidizes alcohols to aldehydes and ketones without overoxidation, prepared from CrO₃, pyridine, and HCl.

Answer 1

The Correct Option is D

To solve this question, we need to identify what PCC (Pyridinium Chlorochromate) is and its composition. PCC is commonly used as an oxidizing agent in organic chemistry.

Let's analyze the given options:

1. K₂Cr₂O₇ + Pyridine: This option refers to potassium dichromate mixed with pyridine. It is not known as PCC.
2. CrO₃ + CHCl₃: This represents chromium trioxide mixed with chloroform. It is not related to PCC.
3. CrO₃ + H₂SO₄: This combination results in chromic acid, which is a different oxidizing agent, not PCC.
4. A complex of chromium trioxide with pyridine + HCl: This is the correct description of PCC. It is formed when chromium trioxide is reacted with pyridine and hydrochloric acid, resulting in the formation of pyridinium chlorochromate (PCC).

Thus, the correct answer is that PCC is a complex of chromium trioxide with pyridine + HCl. This complex is represented by the chemical formula [C_5H_5NH]CrO_3Cl.

PCC is widely used because it can oxidize primary alcohols to aldehydes without further oxidizing them to carboxylic acids, making it a selective oxidizing agent in organic synthesis.