Which of these mixtures constitute buffer solutions? Mixture 1 25 mL of 0.10 M HNO3 and 25 mL of 0.1 — Acids and Bases Chemistry Question

Which of these mixtures constitute buffer solutions?
Mixture 1 25 mL of 0.10 M HNO₃ and 25 mL of 0.10 M NaNO₃
Mixture 2 25 mL of 0.10 M HC₂H₃O₂ and 25 mL of 0.10 M NaOH