When NH3(aq) is added to Cu^2+ (aq) a precipitate initially forms. what is its formula?
To determine the formula of the precipitate formed when NH3 (ammonia) is added to Cu^2+ (copper ions) in aqueous solution, we need to consider the solubility rules.
The reaction can be represented as follows:
Cu^2+ (aq) + 2NH3 (aq) → Cu(OH)2 (s) + 2NH4+ (aq)
The solubility rules state that hydroxides (OH^-) are generally insoluble, except when they are formed with alkali metals (Group 1) and ammonium ions (NH4+).
Therefore, the precipitate formed between Cu^2+ and OH^- ion produced by NH3 will be copper(II) hydroxide, Cu(OH)2.
Hence, the formula for the precipitate formed is Cu(OH)2.