Question

Which of the following will produce a precipitate?

a) Rh3+(aq) + K3PO4(aq)

b) Nb3+(aq) + Li2CO3 (aq)

c) Co2+(aq) + Zn(NO3)2 (aq)

d) K1+(aq) + Na2S (aq)

Answer 1

The correct answer is: c) Co2+(aq) + Zn(NO3)2 (aq)

Precipitation reaction can be defined as the process of the formation of an insoluble salt. An insoluble salt is formed when two solutions containing soluble salts are combined (from its aqueous ions). precipitation reaction refers to the. The insoluble salt that falls out of solution is called precipitate

Answer 2

Answer: The correct answer is Option d.

Step-by-step explanation:

Precipitation reaction is defined as the reaction in which an insoluble salt is formed when two solutions are mixed containing soluble substances. The insoluble salt settles down at the bottom of the reaction mixture.

For the given options:

• Option a:
  `Rh^(3+)(aq.)+K_3PO_4(aq)`

The chemical equation follows:

`Rh^(3+)(aq.)+K_3PO_4(aq.)\rightarrow RhPO_4(aq.)+3K^+(aq.)`

As, no solid product is getting formed, it will not form any precipitate.

• Option b:
  `Nb^(3+)(aq.)+Li_2CO_3(aq)`

The chemical equation follows:

`2Nb^(3+)(aq.)+3Li_2CO_3(aq.)\rightarrow Nb_2(CO_3)_3(aq.)+6Li^+(aq.)`

As, no solid product is getting formed, it will not form any precipitate.

• Option c:
  `Co^(2+)(aq.)+Zn(NO_3)_2(aq)`

The chemical equation follows:

`Co^(2+)(aq.)+Zn(NO_3)_2(aq.)\rightarrow Co(NO_3)_2(aq.)+Zn^(2+)(aq.)`

As, no solid product is getting formed, it will not form any precipitate.

• Option d:
  `K^(+)(aq.)+Na_2S(aq)`

The chemical equation follows:

`2K^(+)(aq.)+Na_2S(aq.)\rightarrow K_2S(s)+2Na^+(aq.)`

As, potassium sulfide is getting formed as a solid. It is considered as a precipitate.

Hence, the correct answer is Option d.