using indicators to find pH (1 Viewer)

[haloeshorns]

ive been told that the pH range of antacid is 8.7-8.9 and ive been given a whole list of indicators and the pH range at which they change colours, and i have to use a combination of these indicators to produce a strategy to accurately determine the pH of antacid.

im pretty much lost on all this stuff and was wondering if anyone had any suggestions? i was thinking maybe titration but i duno how that would work

 

[xiao1985]

you want to find an indicator which changes color just below 8,7 and just above 8.9... say for eg:

you are given that indicators:
A red <--- pH6.8--->blue
B yellow <---- pH 8.5----> blue
C red <----- pH3.3----> yellow
D colorless <----- pH9.0---->pink
E colorless <---- pH 11.1----> purple

you would choose B and D, because you would EXPECT the antacid would be blue in B and colorless in D.... if it's really the case, then you know the antacid you got has the pH between 8.5 and 9.0