Question

What is the H^+ ion concentration in a 2.1x10^-4 M Ca(OH)2 solution? Please explain in detail and do step by step. Thanks!

Answer 1

1Ca(OH)2 >Ca*2+20H 1mol of Ca(OH)2 producing 2 moles of OH Concentration of Ca(OH)2 2.1×10-4M Concentration of OH- 2x (2.1x10-M) = 4.2x10-4 M [H+] = Kw [OH-] =12.38×10-11M [H]-_1x10-14 - 4.2× 10-4

Answer 2

Ca(OH)₂   $\rightarrow$     Ca²⁺ + 2OH^-

Here, we can see that one mole of Ca(OH)₂ produces two moles of OH^-

Therefore, concentration of OH^- = [OH-] = 2 x (2.1x10^-4 M ) = 4.2 x 10^-4 M

We have, [H⁺][OH^-] = Kw (Kw = 1 x 10^-14 )

Therefore, [H⁺] = (1 x 10^-14) /(4.2 x 10^-4 M) = 2.3809 x 10^-11 M

H⁺ ion concentration in a 2.1x10^-4 M Ca(OH)² solution = 2.3809 x 10^-11 M