Write the balanced chemical equation for the reaction. Include phases.

Question

When aqueous sodium hydroxide is added to a solution containing lead(II) nitrate, a solid precipitate forms.

However, when additional aqueous hydroxide is added, the precipitate redissolves, forming a soluble complex ion.

Answer 1

The first reaction is the formation of the precipitate of lead hydroxide.

2NaOH(aq) + Pb(NO₃)₂(aq) ==> Pb(OH)₂(s) + 2NaNO₃(aq)

The next reaction is that of the precipitate reacting with excess base to produce the soluble lead complex

Pb(OH)₂(s) + 2OH^-(aq) ==> Pb(OH)₄^2-(aq)