Question

Which is the set of amphiprotic species?
A.${H_3}{O^ + },HP{O_4}^{ - 2},HC{O_3}^ -$
B.${H_2}P{O_4}^ - ,{H_2}P{O_3}^ - ,{H_2}O$
C.${H_2}P{O_4}^ - ,{H_2}P{O_3}^ - ,{H_2}O$
D. All of these

Answer 1

We can solve the given problem with the concept of amphoterism. The amphoteric words means both. So the amphoteric species are those species which act as both acid and base depending on medium. This property depends on the oxidation states of the element.

Complete step by step answer:
An acid is a hydrogen – containing compound, which gives free hydrogen ions H+ when dissolved in water. We can take an example of $HCl$ , when hydrochloric acid ionizes as:$HCl + {H_2}O \to {H_3}O + C{l^ - }$ . A base is a compound that gives higher concentration of $O{H^ - }$ ions when dissolved in water. This dissociation reaction can be presented as: $NaOH \to N{a^ + } + O{H^ - }$ .
So the sodium hydroxide $NaOH$ dissociates into the sodium and hydroxide ions when dissolved in the water, then there is releasing $O{H^ - }$ ions into solution.
Amphoteric species behave like acids when they present in basic medium and behave like base when present in acidic medium because they can accept or donate a proton according to need.

In the given question, ${H_2}P{O_4}^ - ,{H_2}P{O_3}^ - ,{H_2}O$ is the set of amphiprotic species. So option C is the correct answer to this problem. We have studied the conjugate acid and conjugate base. When acid donates a proton the acid changes into base means the formed species is known as conjugate base and vice versa .Amphiprotic species can behave both like an acid and a base. They can donate or accept a proton. So, the correct answer is “Option C”.

Note: An amphiprotic molecule can either donate or accept a proton, thus acting either as an acid or base. Water , amino acids, hydrogen carbonate ion (bicarbonate ion) and hydrogen sulphate ion are common examples of amphiprotic species.