Question

I am doing triprotic acid titrations.

I have an imaginary acid (H3A) 10mL with the concentration 0.760M and we are titrating a NaOH with the concentration of 0.320M.

I have to find the amount of NaOH in mol and mL for

1. first half-equivalence point

2.first equivalence point

3. second-half equivalence point

4.second equivalence point

5. third half-equivalence point and

6. third equivalence point.


and then I have to find the pH for each of these points.

Answer 1

amount of NaOH in mol for every point: (0.76/100)/(2/№point)= 0.0038; 0.0076; 0.0114; 0.0152; 0.019; 0.0228

amount of NaOH in mL for every point: n/0.000320= 11.875; 23.75; 35.63; 47.5; 59.38; 71.25

pH for every point: pH=-lg(C_H3AK₁+C_H2A+K₂+C_HAK₃)^1/2