[Mvelarde]

Good morning to all,
A packet contains a mixture of magnesium carbonate (31%), citric acid (65%), and potassium citrate (3%) which, when dissolved in 240 mL of water, yields a solution containing 16,4 g magnesium citrate.
I need the chemical reaction to obtain this 16,4 g magnesium citrate.
Thanks.

[discodermolide]

Try writing a balanced equation for this reaction, for that you will have to find out the structures of the various compounds you mentioned.