Question

Thymolphthalein is an indicator that changes color over a range from pH=9.3 to pH=10.5. What is Ka of thymolphthalein?

Answer 1

According to Hasselbalch equation pH = pKa at the equal point. When pH equals the pKa value of the indicator, the base and acid forms of indicator are present in the ratio of 1:1 

(9.3 + 10.5) / 2 =9.9
pKa = 9.9
Using the equation pH = pKa at equal point we get
Ka = 10^- pKa
Ka = 10^- 9.9
Ka = 1.26 x 10^-10
Ka = 1 x 10^-10

Answer 2

The  Ka of thymolphthalein is mathematically given as

Ka = 1 x 10^{-10 }

What is Ka of thymolphthalein?

Question Parameters:

an indicator that changes color over a range from pH=9.3 to pH=10.5.

Generally, the pKa  of thymolphthalein is mathematically given as

Pka=(9.3 + 10.5) / 2

Pka=9.9

Therefore

pH = pKa

Ka = 10^- pKa

Ka = 1.26 x 10^-10}

Ka = 1 x 10^{-10 }

Read more about Chemical

https://brainly.com/question/6876669