$H_2SO_4(aq)$ is an acid according to the Arrhenius definition.
Work Step by Step
According to the Arrhenius definition, an acid is a substance which produces $H^+$ ions in an aqueous solution. As we can see from the below equation, $H_2SO_4(aq) \rightarrow 2H^+(aq) + SO_4^-(aq)$ $H_2SO_4$ produces $H^+$ ions in aqueous solutions. So it is an acid.