Question

Which equations represent precipitation reactions?

Answer 1

In a precipitation reaction, one of the product formed is an insoluble precipitate.

The given reactions can be written with phases included as:

A. $Na_{2}S(aq)+FeBr_{2}(aq)-->2NaBr(aq)+FeS(s)$: In this reaction one of the product, FeS is insoluble. Therefore, this is a precipitation reaction.

B. $MgSO_{4}(aq)+CaCl_{2}(aq)-->MgCl_{2}(aq)+CaSO_{4}(s)$: In this reaction, the product $CaSO_{4}$is a solid(insoluble). So, this is a precipitation reaction too.

C.$LiOH(aq)+NH_{4}I(aq)-->LiI(aq)+NH_{4}OH(aq)$: In this reaction, both the products are soluble. So this is not a precipitation reaction.

D.$2NaCl(aq)+K_{2}S(aq)-->Na_{2}S(aq)+2KCl(aq)$: In this reaction, both the products are soluble. So this is not a precipitation reaction.

E. $AgNO_{3}(aq)+NaCl(aq)-->AgCl(s)+NaNO_{3}(aq)$: In this reaction, the product AgCl is a precipitate. So, it is a precipitation reaction.