Question

In which of the following reactions $H_{2}O$acts as a Bronsted acid?

• A. $H_{2}O_{(l)} + NH_{3(aq)}$ $O{H^{-}}_{(aq)} + NH_{4(aq)}^{+}$
• B. $H_{2}O_{(l)} + H_{2}S_{(aq)}$ $H_{3}{O^{+}}_{(aq)} + H{S^{-}}_{(aq)}$
• C. $H_{2}O_{(i)} + H_{2}O_{(I)}$ $H_{3}{O^{+}}_{(aq)} + O{H^{-}}_{(aq)}$
• D. ${H^{+}}_{(aq)} + O{H^{-}}_{(aq)}$ $H_{2}O_{(I)}$

Answer 1

Answer: (A)

$H_{2}O_{(l)} + NH_{3(aq)}$ $O{H^{-}}_{(aq)} + NH_{4(aq)}^{+}$

Answer 2

: $H_{2}O$acts as a Bronsted acid and gives proton to react with a base.

$\underset{Acid}{H_{2}O} + \underset{base}{NH_{3}}$ $OH^{-} + NH_{4}^{+}$

In $\underset{base}{H_{2}O} + \underset{acid}{H_{2}S} \rightarrow H_{3}O^{+} + HS^{-}$

$H_{2}O$acts as a base with $H_{2}S$