You Are Working on a Project to Recycle Nickel and Cadmium

Multiple Choice

You are working on a project to recycle nickel and cadmium from old nickel-cadmium batteries that have an iron casing.The batteries are dissolved in aqueous nitric acid, producing a solution containing primarily Ni²⁺, Cd²⁺, and Fe³⁺ cations.One idea is to add sodium hydroxide to neutralize the acid and cause precipitation of Ni(OH) ₂, Cd(OH) ₂, and Fe(OH) ₃.Assume the concentration of each of the cations is 0.100 M before the sodium hydroxide is added.The pH increases as the sodium hydroxide is added.Which compound will precipitate first, and what is the pH at that point?

A) Cd(OH) ₂; pH = 9.16
B) Fe(OH) ₃; pH = 4.81
C) Fe(OH) ₃; pH = 1.93
D) Cd(OH) ₂; pH= 6.42
E) Ni(OH) ₂; pH =7.24