First think about what will be reacting in the titration. The NaOH will react in an acid-base reaction with the carboxylic acid. As the carboxylic acid is a weak acid, and NaOH is a strong base, you would get a titration curve like the one attached.
So you need the indicator which changes colour in the range of the straight line section which is phenolphthalein. Hope this helps!
First think about what will be reacting in the titration. The NaOH will react in an acid-base reaction with the carboxylic acid. As the carboxylic acid is a weak acid, and NaOH is a strong base, you would get a titration curve like the one attached.
So you need the indicator which changes colour in the range of the straight line section which is phenolphthalein. Hope this helps!
And this is why I'm failing all my exams because I can't read questions The only thing I can think of is the titre value is the amount needed to neutralise the HCl and carboxylic acid but I'm not sure about the indicator if that's the case, sorry.