Question

Find [cu2+] in a solution saturated with cu4(oh)6(so4) if [oh − ] is fixed at 2.3 ✕ 10−6 m. note that cu4(oh)6(so4) gives 1 mol of so42− for 4 mol of cu2+.

Answer 1

$Cu_4(OH)_6(SO_4)$

You have OH-  conc = 2.3 ✕ 10−6 m
From the formula, you can observe the ratio of Cu2+ to OH- is  4 : 6 = 2:3

So, for 2.3 ✕ 10−6 m OH-
[Cu2+] = $\frac{2}{3} \times 2.3 \times 10^{-6}$

$= 1.53 \times 10^{-6}$