Answer: The combination of 100 mL of 1.0 M CH3NH2 and 100 mL of 0.50 M CH3NH3 would result in a buffer solution.
Step-by-step explanation:
A buffer solution is a solution that can resist changes in pH upon the addition of an acid or a base. To form a buffer solution, we need a weak acid (or base) and its conjugate base (or acid) in similar concentrations.
Option 1: 100 mL of 1.0 M HCl and 50.0 mL of 1.0 M NaCl
This is not a buffer solution because HCl is a strong acid and NaCl is a neutral salt, which does not have an acidic or basic effect on the solution.
Option 2: 100 mL of 1.0 M HNO2 and 100 mL of 2.0 M NaNO2
This is not a buffer solution because HNO2 is a weak acid, but NaNO2 is not its conjugate base. Instead, NaNO2 hydrolyzes to form NaOH and HNO2, which decreases the buffer capacity.
Option 3: 100 mL of 1.0 M CH3NH2 and 100 mL of 0.50 M CH3NH3
This is a buffer solution because CH3NH2 is a weak base and CH3NH3+ is its conjugate acid. They are in similar concentrations, and therefore, can resist changes in pH upon the addition of an acid or a base.
Option 4: 100 mL of 1.0 M HF and 50.0 mL of 1.0 M HClO
This is not a buffer solution because HF is a weak acid, but HClO is not its conjugate base. Instead, HClO hydrolyzes to form H3O+ and ClO-, which decreases the buffer capacity.