Question

Acetic anhydride and sulphuric acid are reagents used in

• A. Shinoda's test
• B. Borntrager's test
• C. Liebermann Burchard test
• D. Murexide test

Hint:

Each chemical test in pharmacognosy uses a specific set of reagents to identify a particular group of compounds. Remembering the reagent–test pairing answers the question.

Answer 1

The Correct Option is C

Step 1: Know the common phytochemical tests.
Different classes of plant compounds have specific colour tests. Memorising the reagents helps identify the test.

Step 2: What is the Liebermann-Burchard test?
This test is used for the detection of sterols and triterpenoids (e.g., cholesterol, phytosterols). The reagents are acetic anhydride and concentrated sulphuric acid. A positive result shows a green or blue-green colour.

Step 3: Why not the other tests?
Shinoda’s test uses magnesium ribbon and hydrochloric acid to detect flavonoids. Bornträger’s test uses KOH to detect anthraquinone glycosides; the solution turns pink or red. Murexide test uses nitric acid followed by ammonia to detect purines.

Step 4: Confirm the reagents match.
Acetic anhydride + H₂SO₄ = Liebermann-Burchard. This is a direct recall fact widely asked in pharmacognosy.

Step 5: Conclude.
The combination of acetic anhydride and sulphuric acid is the hallmark of the Liebermann-Burchard test for sterols.

Answer: Option (3) — Liebermann Burchard test