Question

Let us assume that Cd(OH)2(s) is completely insoluble, which signifies that the precipitation reaction with NaOH(aq) (presented in the transition) would go to completion.

Cd2+(aq)+2NaOH(aq) → Cd(OH)2(s)+2Na+(aq)

If you had a 0.300 L solution containing 0.0220 M of Cd2+(aq) , and you wished to add enough 1.25 M NaOH(aq) to precipitate all of the metal, what is the minimum amount of the NaOH(aq) solution you would need to add? Assume that the NaOH(aq) solution is the only source of OH−(aq) for the precipitation.

Answer 1

The minimum amount of NaOH(aq) solution needed to add is 0.0560 L. This can be calculated by using the following equation:

Moles of Cd2+ = 0.0220 M x 0.300 L = 0.0066 mol

Moles of NaOH = 0.0066 mol x 2 = 0.0132 mol

Volume of NaOH = 0.0132 mol/1.25 M = 0.0560 L

Step-by-step explanation: