Question

Calculeaza pH-ul unesi solutii de aminiac de concentratie 0,005 M ( K NH₃=1,8*10⁻⁵ ) 
b) Calculeaza pH-ul unei solutii de acid acetic ( CH₄COOH) 0,1 M ( K acidacetic=1,8*10⁻⁵ M)

Answer 1

1)[H3O+] = $\sqrt{cM * Kb} = \sqrt{0,005 * 1,8 * 10 la -5} = 3 * 10 la -4$
pH = - lg [H3O+] = - lg 3 * 10 la -4 = 8,11

2)[H3O+] = $\sqrt{cM*Ka} = \sqrt{0,1 * 1,8 * 10 la -5} = 1,34 * 10 la -3$
pH = - lg [H3O+] = - lg 1,34 * 10 la -3 = 6,61