Question

which of the following shows a bronsted - lowry acid reacting?
co + no2 → co2 + no
nh3 + h+ → nh4+
co32- + h+ → hco3-
hcl + h2o → h3o+ + cl-

Explanation:

A Brønsted - Lowry acid is a substance that donates a proton ($H^+$). In the reaction $HCl + H_2O
ightarrow H_3O^+ + Cl^-$, $HCl$ donates a proton to $H_2O$. In the other reactions, the species are either accepting a proton (acting as bases) or the reaction does not involve proton - transfer in the Brønsted - Lowry sense.

Answer:

$HCl + H_2O
ightarrow H_3O^+ + Cl^-$