Question

What is the activity coefficient of H in a solution containing 0.070 M HCl and 0.010 M Ca(ClO4)2? A table of activity coefficients at various ionic strengths can be found here.

Number: 0.8222

What is the Ph Solution: Number?

Answer 1

First, we find the value of miu (u) for this. This would be the ionic strength

u = (0.070)*1² + (0.070)(-1)² + (0.010)(2)² + (0.010)(-1)² / 2

u = 0.095

Now to calculate the activity coefficient, use the following expression:

logY = -0.51z² (u)^1/2 / 1 + (au^1/2/305)

Y is activity coefficient

a or alpha is the size of H⁺ which is 900 pm.

Replacing all the values we have:

logY = -0.51(1)² (0.095)^1/2 / 1 + (900(0.095)^1/2 / 305)

logY = -0.15719 / 1.9095

Y = 10^(-0.0823)

Y = 0.8273

For the pH:

pH = -log([H⁺]Y)

pH = -log (0.07*0.8273)

pH = 1.24

Hope this helps