Which of these mixtures constitute buffer solutions?

Mixture 1 : $25 \mathrm{mL}$ of $0.10\mathrm{M} {\mathrm{HNO}}_3$ and $25 \mathrm{mL}$ of  $0.10\mathrm{M} {\mathrm{NaNO}}_3$

Mixture 2 : $25 \mathrm{mL}$ of $0.10\mathrm{M} {\mathrm{HC}}_2{\mathrm{H}}_3{\mathrm{O}}_2$ and $25 \mathrm{mL}$ of $0.10\mathrm{M} \mathrm{NaOH}$.

${\mathrm{HNO}}_3$ is strong acid. A weak acid and the conjugate base of the weak acid, or a weak base and the conjugate acid of the weak base, are combined to form the buffer solution, a water-based solvent solution.

None of the mixture has buffer.