Multiple choice

Which of the following are used as counterstain in Gram staining technique? P. Crystal violet Q. Safranin R. Iodine solution S. Carbol fuchsin Select the correct answer.

  1. P and Q

  2. P and R

  3. Q and R

  4. Q and S

  5. R and S

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Safranin is used as secondary stain (counterstain) in Gram staining technique. Carbol fuchsin is sometimes substituted for safranin as counterstain, since it  more intensely stains anaerobic bacteria.