Answer:
H₂SO₄
Explanation:
A Brønsted acid is a proton donor. It loses protons.
This equation may be easier to understand if we write it ionically.
[tex]\underbrace{\hbox{H$_{2}$SO$_{4}$}}_{\hbox{Br$\o{}$nsted acid}} + 2 \text{NH}_{3} \longrightarrow \, \underbrace{\hbox{SO$_{4}^{2-}$}}_{\hbox{Br$\o{}$nsted base}} + \text{2 NH}_{4}^{+}[/tex]
We see that the H₂SO₄ has lost two protons to become SO₄²⁻, so it is a Brønsted acid.
