Question

If 1 liter solution has 4.4mol HCl, 4.6mol NaOH and 0.50mol HA is added together what is the pH when the resulting solution reaches equilibrium?

Answer 1

As we can see from the question that no. of moles of H+ are 4.4+0.50.hence total no. of H+ moles= 4.9.

No.of moles of OH- are 4.6 moles.

Hence 4.6 moles of H+ will react with 4.6 moles of OH- .to form 4.6 moles of H2O.

Thus (4.9-4.6) moles of H+ will remain unreacted.Hence pH of resultant 1 litre solution in equilibrium is to be calculated.

concentration of H+ ion= No. of moles/no. of litres of solution

= 0.3/1= 0.3M

pH= -(log(H+)) = -(log(0.3))= 1-0.4771 = 0.5229.