[azmodan]

Hello,

I seriously need help with that 2 question.

1-)
Three solutions contain methanoic acid (HCOOH, pKa = 3.75) at a concentration of 0.2 mol/L and sodium methanoate at concentrations of:
(i) 0.1 mol/L
(ii) 0.2 mol/L
(iii) 0.4 mol/L
Calculate the pH of these three solutions

2-)
Calculate the pH of a 0.05 mol/L solution of acetic acid, which has a dissociation constant (Ka) of 1.76x10–5 mol/L.

I have difficulty in refreshing my mind in chemistry so I need your help.

Thank you so much.

[Hunter2]

Keyword Henderson-Hasselbalch equation