Lead (II) hydroxide precipitate, 2 of 3. Lead (II) hydroxide precipitate (Pb (OH)2) formed by adding 0.25 M lead nitrate (Pb (NO3)2) solution to 0.5 M solution of potassium hydroxide (KOH). The reaction is Pb (NO3)2 + KOH -> Pb (OH)2 + KNO3. This is an example of a double replacement reaction.