An acid-base indicator has Ka = 3  10-5. The acid form of the indicator is red and the basic form o — AITS & Test Series Chemistry Question

Question

An acid-base indicator has Ka = 3  10-5. The acid form of the indicator is red and the basic form of the indicator is blue. By how much must the pH change in order to change the indicator from 75% red to 75% blue? [log 3 = 0.4770] (A) 4.05 (B) 0.95 (C) 5 (D) 9