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)

Option (A) is the correct answer.

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,

Here, is the precipitate.

Thus, we can conclude that out of the given options, the reaction is an example of a precipitation reaction.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).