Answer
a. $ NaOH$ is a base.
$$NaOH(aq) \longrightarrow Na^+(aq) + OH^-(aq)$$
b. $H_2SO_4$ is an acid.
$$H_2SO_4(aq) \longrightarrow HS{O_4}^-(aq) + H^+$$
c. $HBr$ is an acid.
$$HBr(aq) \longrightarrow H^+(aq)+ Br^-(aq)$$
d. $Sr(OH)_2$ is a base.
$$Sr(OH)_2(aq) \longrightarrow Sr^{2+}+2OH^-(aq)$$
Work Step by Step
1. According to Arrhenius' definition, an acid is a substance that produces $H^+$ ions in aqueous solution. Therefore, they must have a disponible $H^+$ in their structures, like $H_2SO_4$ and $HBr$.
2. According to the same scientist, bases are substances that produce $OH^-$ ions in aqueous solution. Therefore, they must have a disponible $OH^-$ like $NaOH$ and $Sr(OH)_2$.
3. The chemical equation is basically the substance ionizing, separating their ions.
