What is the approximate pH of a 1 M solution of Na2CO3Soluti

What is the approximate pH of a 1 M solution of Na₂CO₃?

Solution

You\'d have to mix the Na2CO3 with H2O first, so that there will be an [OH] to compute the pH from. :)

Na2CO3 --> 2Na+ + (CO3)^(-2)

Then the CO3(2-) anion reacts with water:

CO3(2-) + H2O <==> HCO3(-) + OH-


Kb = [HCO3][OH]/[CO3][H2O]
2*10^(-4) = x^2/[1M][1]
x=1.414 x 10^-2 M

pOH = -logx
=1.85

pH = 14 -pOh
= 12.15