Question

Magnesium is precipitated from its salt solution as only magnesium ammonium phosphate by adding disodium hydrogen phosphate solution in absence of ammonium chloride and aqueous ammonia.

Answer 1

Precipitation is carried out in presence of ammonium chloride and aqueous ammonia as they prevent precipitation of magnesium hydroxide.
`Mg^(2+)+NH_(3)+HPO_(4)^(2-)toMg(NH_(4))PO_(4)darr`(white)