Answer:- [tex]\frac{[In^-]}{[HIn]}=3.16*10^-^8[/tex]
Solution:- If both acid and basic form are present at the same time then it's like a buffer solution since the buffer solution also has a weak acid and its conjugate base. The Handerson equation is used for solving buffer problems. Let's use the same equation here also.
The equation is:
[tex]pH=pKa+log(\frac{[base]}{[acid]})[/tex]
pKa is given as 9.7 and the pH is 2.2. let's plug in the values in the equation.
[tex]2.2=9.7+log(\frac{[In^-]}{[HIn]})[/tex]
subtract 9.7 from sides:
[tex]2.2-9.7=log(\frac{[In^-]}{[HIn]})[/tex]
[tex]-7.5=log(\frac{[In^-]}{[HIn]})[/tex]
taking antilog:
[tex]10^-^7^.^5=\frac{[In^-]}{[HIn]}[/tex]
[tex]3.16*10^-^8=\frac{[In^-]}{[HIn]}[/tex]
So, the answer is [tex]3.16*10^-^8[/tex] .
3.16 × 10⁻⁸ is the value of [In−]/[HIn], when the pH of the solution is 2.2.
What is Henderson Equation?
Henderson equation is used to calculate the pH of the buffer solution and it is represented as:
pH = pKa + log([base]/[acid])
In the question given that:
pH of solution= 2.2
pKa of phenolphthalein = 9.7
On putting these values on the above equation, we get
2.2 = 9.7 + log[In−]/[HIn]
log[In−]/[HIn] = -7.5
[In−]/[HIn] = 3.16 × 10⁻⁸
Hence, the value of [In−]/[HIn] is 3.16 × 10⁻⁸.
To know more about Henderson equation, visit the below link:
https://brainly.com/question/14602381
