[JNW2]

(Following this https://www.physicsforums.com/threads/solution-of-salt-of-a-weak-base-and-salt-of-a-weak-acid.813479/)

:Having 1.00 L solution containing 3 moles of NaCH3COO and 2 moles of NH4Cl . find pH.

Attempt to solve the problem:
Step 1: there are CH3COO- , NH4+ ,(H+ ,OH- from water autolysis)

[AWK]

Without ionic strenght correction treat this solution as 1 M CH₃COONa tentatively, but this be only the upper limit for pH since formally 2 M CH₃COONH₄ works as buffer with high capacity in both directions +pH and -pH. Concentrations of salts are so high that no calculations, even advanced scientific ones will not work exactly. Only measurements can show proper pH.

[JNW2]

Without ionic strenght correction treat this solution as 1 M CH₃COONa tentatively, but this be only the upper limit for pH since formally 2 M CH₃COONH₄ works as buffer with high capacity in both directions +pH and -pH. Concentrations of salts are so high that no calculations, even advanced scientific ones will not work exactly. Only measurements can show proper pH.

If I change condition to 0.03 M and 0.02 M of these salts.
How will the calculation work?

[AWK]

Without computer program, and without iterations I can say that pH is between 7 and 8.4

[JNW2]

Without computer program, and without iterations I can say that pH is between 7 and 8.4

More Hints ,please.

[AWK]

http://www.chembuddy.com/?left=pH-calculation&right=pH-salt-solution

http://www.had2know.com/academics/quartic-equation-solver-calculator.php

[JNW2]

http://www.chembuddy.com/?left=pH-calculation&right=pH-salt-solution

http://www.had2know.com/academics/quartic-equation-solver-calculator.php

Using your link
let x be [H+]
I get the answer by wolfram alpha online (http://m.wolframalpha.com/input/?i=0.112x10%5E%28-10%29%2F%28x%2B5.6x10%5E%28-10%29%29%2B1x10%5E%28-14%29%2Fx%3D0.03x%2F%28x%2B1.8x10%5E%28-5%29%29%2Bx&x=0&y=0)

x= 8.18945x10^(-8)
pH =8-log 8.18945 =7.09

[AWK]

And this value make sense.