An amphoteric substance is one that can act as both an acid and a base.
This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
ScanSolve AI Answer
An amphoteric substance is one that can act as both an acid and a base.
Let's examine each option:
A- $\text{HCO}_3^{-}$ (Bicarbonate ion):
Can act as an acid by donating a proton: $\text{HCO}_3^{-} \rightleftharpoons \text{CO}_3^{2-} + \text{H}^{+}$
Can act as a base by accepting a proton: $\text{HCO}_3^{-} + \text{H}^{+} \rightleftharpoons \text{H}_2\text{CO}_3$
Thus, $\text{HCO}_3^{-}$ is amphoteric.
B- $\text{NH}_3$ (Ammonia):
Can act as an acid by donating a proton (e.g., in reactions with very strong bases or in autoionization): $\text{NH}_3 \rightleftharpoons \text{NH}_2^{-} + \text{H}^{+}$
Can act as a base by accepting a proton: $\text{NH}_3 + \text{H}^{+} \rightleftharpoons \text{NH}_4^{+}$
Thus, $\text{NH}_3$ is amphoteric.
C- $\text{H}_2\text{O}$ (Water):
Can act as an acid by donating a proton: $\text{H}_2\text{O} \rightleftharpoons \text{OH}^{-} + \text{H}^{+}$
Can act as a base by accepting a proton: $\text{H}_2\text{O} + \text{H}^{+} \rightleftharpoons \text{H}_3\text{O}^{+}$
Thus, $\text{H}_2\text{O}$ is amphoteric.
Since all three substances ($\text{HCO}_3^{-}$, $\text{NH}_3$, and $\text{H}_2\text{O}$) exhibit amphoteric behavior, the correct option is D.
The final answer is $\boxed{\text{D- All of the above}}$.
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