Question

Match List-I with List-II.

List - I		List - II
A.	Iodine	I.	Primary stain
B.	Alcohol	II.	Decolorizer
C.	Safranin	III.	Counter stain
D.	Crystal Violet	IV.	Mordant

Choose the correct answer from the options given below:

• A. A-II, B-III, C-IV, D-I
• B. A-I, B-III, C-II, D-IV
• C. A-I, B-II, C-IV, D-III
• D. A-IV, B-II, C-III, D-I

Hint:

In Gram staining, crystal violet is primary stain, iodine is mordant, alcohol is decolorizer and safranin is counter stain.

Answer 1

The Correct Option is D

Concept:
Gram staining uses different reagents in a proper order to differentiate Gram-positive and Gram-negative bacteria.

Step 1: Match iodine.
Iodine acts as a mordant in Gram staining. \[ A\rightarrow IV \]

Step 2: Match alcohol.
Alcohol is used as a decolorizer. \[ B\rightarrow II \]

Step 3: Match safranin.
Safranin is used as a counter stain. \[ C\rightarrow III \]

Step 4: Match crystal violet.
Crystal violet is the primary stain. \[ D\rightarrow I \] Therefore, the correct matching is: \[ A-IV,\ B-II,\ C-III,\ D-I \] \[ \therefore \text{Correct Answer is (D)} \]