Question
Chemistry Question on Acid-base titrations
Which indicator is used in the titration of sodium hydroxide against oxalic acid and what is the colour change at the end point?
A
Phenolphthalein, pink to yellow
B
Alkaline KMnO4, colourless to pink
C
Phenolphthalein, colourless to pink
D
Methyl orange, yellow to pinkish red colour
Answer
Phenolphthalein, colourless to pink
Explanation
Solution
Phenolphthalein is a suitable indicator for the titration of a strong base (sodium hydroxide) against a weak acid (oxalic acid). The end point is indicated by a colour change from colourless in acidic solution to pink in basic solution.