Question

In V group, (NH₄ ) 2CO₃ is added to precipitate out the carbonates. We do not add Na₂CO₃ along with NH₄Cl because 

(A) CaCO₃ is soluble in Na₂CO₃ 

(B) Na₂CO₃ increase the solubility of V group carbonate. 

(C) MgCO₃ will be precipitated out in V group 

(D) None of these 

Answer 1

Correct Answer is: (C) MgCO₃ will be precipitated out in V group

Na₂CO₃ produces large [CO₃^2–] which may ppt other cations along with Ba²⁺, Sr²⁺ and Ca²⁺ which interfere the detection of group V cation.