Question

Which reaction is an example of a precipitation reaction?

(A) FeCl3 (aq) + 3 KOH (aq) → Fe(OH)3 (s) + 3 KCl (aq)
(B)2 Hg (l) + O2 (g) → 2 HgO (s)
(C)H2CO3 (aq) → H2O (l) + CO2 (g)
(D)H2SO4 (aq) + Ca(OH)2 (aq) → CaSO4 (aq) + 2 H2O (l)
(E)6 HCl (aq) + 2 Al (s) → 2 AlCl3 (aq) + 3 H2 (g)

Answer 1

(A) FeCl3 (aq) + 3 KOH (aq) → Fe(OH)3 (s) + 3 KCl (aq)

Step-by-step explanation:

A precipitation reaction happens when a solid (called a precipitate) is formed due the reaction between anions and cations that were previously in aqueous solution.

In B there were no cations or anions that interacted

In C, and D, cations and anions interacted but no solid (precipitate was formed)

In E the cations interacted with a solid and no precipitate was formed.

Answer 2

Answer: Option (A) is the correct answer.

Step-by-step explanation:

When two aqueous solutions chemically combine together then there is a possibility that an insoluble solid substance might form. This insoluble substance is known as a precipitate and this type of reaction is known as precipitation reaction.

For example,
`FeCl_(3)(aq) + 3KOH(aq) \rightarrow Fe(OH)_(3)(s) + 3KCl(aq)`

Here,
`Fe(OH)_(3)(s)` is the precipitate.

Thus, we can conclude that out of the given options, the reaction
`FeCl_(3)(aq) + 3KOH(aq) \rightarrow Fe(OH)_(3)(s) + 3KCl(aq)` is an example of a precipitation reaction.