Which indicator is best suited for the titration of 0.05 M HOCl (pK_a = 7.54) with 0.05 M NaOH? ...


Which indicator is best suited for the titration of {eq}\rm 0.05\ M\ HOCl\ (pK_a = 7.54) {/eq} with {eq}\rm 0.05\ M\ NaOH {/eq}?

1) Thymolphthalein {eq}\rm (pK_{HIn} = 9.85) {/eq}.

2) Methyl red {eq}\rm (pK_{HIn} = 5.30) {/eq}.

3) Phenol red {eq}\rm (pK_{HIn} = 7.60) {/eq}.

4) Bromophenol blue {eq}\rm (pK_{HIn} = 3.80) {/eq}.

5) Alizarin yellow-R {eq}\rm (pK_{HIn} = 11.15) {/eq}.

Titration Indicator:

In order to easily identify the equivalence point of a titration process, indicators are placed in the solution containing the analyte before allowing it to react with the titrant. These indicators are substances whose color changes upon the change in pH value. For a titration process, ideal indicators that have pKa values close to the endpoint's pH value, and can easily change color at that point.

Answer and Explanation: 1

Become a Study.com member to unlock this answer!

View this answer

First, we will calculate the pH at the equivalence point. We will assume that we have 100 mL of HOCl and 100 mL of NaOH. Take note that at the...

See full answer below.

Learn more about this topic:

Titrations with Weak Acids or Weak Bases


Chapter 11 / Lesson 10

Learn about titrations of weak acids and strong bases, strong acids and weak bases, and weak acids and weak bases. Explore types of titration curves and the pH.

Related to this Question

Explore our homework questions and answers library