In aqueous solution, ammonia is in equilibrium with water: $\text{NH}_3 + \text{H}_2\text{O} \rightleftharpoons \text{NH}_4^+ + \text{OH}^-$. Within this equilibrium, which particle is the acid and which particle is the base?
- Aacid: $\text{NH}_3$; base: $\text{H}_2\text{O}$
- Bacid: $\text{NH}_3$; base: $\text{OH}^-$
- Cacid: $\text{H}_2\text{O}$; base: $\text{NH}_3$
- Dacid: $\text{H}_2\text{O}$; base: $\text{NH}_4^+$