Question

Is $ {H_3}{O^ + } $ an electrophile?

Answer 1

Hint :Hydronium is the common name for the aqueous cation, the type of oxonium ion produced by protonation of water. It is the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton to the surrounding molecule.

Complete Step By Step Answer:
  $ {H_3}{O^ + } $ has a lone pair of electrons, but due to the presence of a positive charge, it can’t donate its electron pair. Hence it doesn’t act as a nucleophile. Whereas it was able to donate h+ ion to nucleophiles by accepting a pair of electrons and so $ {H_3}{O^ + } $ act as an electrophile.
The hydronium ion is an important factor when dealing with chemical reactions that occur in aqueous solution. Its concentration relative to hydroxide is a direct measure of the pH of a solution. The hydronium ion has a trigonal pyramidal geometry and is composed of three hydrogen atoms and one oxygen atom.
The water molecule dissociates while the $ O{H^ - } $ ions combine with the h ions to form water. Water has the ability to attract $ {H^ + } $ ions because it is a polar molecule. This means it has partial charge, in this case the charge is negative, the partial charge is caused by the fact that oxygen is more electronegative than hydrogen.
An overall reaction for the dissociation of water to form hydronium can be seen here:
 $ 2{H_2}O(l) \rightleftharpoons O{H^ - }(aq) + {H_3}{O^ + }(aq) $
The pH of a solution depends on its hydronium concentration. The pH can either go up or down depending on the charge in hydronium concentration. If the hydronium concentration increases, the pH decreases, causing the solution to become more acidic.
This happens when an acid is introduced. As $ {H^ + } $ ions dissociate from the acid and bond with water, they form hydronium ions, thus increasing the hydronium concentration of the solution.

Note :
Hydronium not only forms a result of the dissociation of water, but also forms when water is in presence of an acid. As the acid dissociation, the $ {H^ + } $ ions bond with water molecule to form hydronium, as seen here when hydrochloric acid is in the presence of water:
 $ HCl(aq) + {H_2}O \to {H_3}{O^ + }(aq) + C{l^ - }(aq) $