Question

Hsuannn

化學 PH值計算（多質子酸解離）
請問這題錯在哪裡呢😭

0.3M Na2HPO4
Example #1: Determine the pH of 0.300 M sodium hydrogen phosphate, Na₂HPO4.
Phosphoric acid, H3PO4, contains K₁₁ = 7.5 x 10-3, K₂ = 6.2 x 10-8 and K₁3 = 4.2 x 10-13.
al
a2
a3
x²
0.2x=4.2X10-13
x² = 1.26×10-¹3/- 0.₁126×10/2
x = 0.355x100
HP04² = H30t+ P04²
0.3
0.3-X
+x +X
X X
3-
04-beg[+0]- (6.459.78
PH=
Simp
-6

化學

Answer 1

Alstormeria5

I would say this problem is a problem per se. So I give you the result calculated by wolfram nonlinear equation solver.however,if this problem is indeed in an exam,the only possible answer as a man can get is either the first equivalent point or the second equivalent point of phosphoric acid titration.But the fact that ph value (9.78) appears to be basic is pretty weird so it’s for you to decide is this problem worth for study.

Alstormeria5

A method to achieve the result in the previous post