When the following solutions are mixed, which will act as a buffer? (check all that apply)

A. 50 mL of 0.05M sodium hydroxide and 50 mL of 0.1M nitrous acid

B. 50 mL of 0.1M ammonia and 50 mL of 0.1M ammonium acetate

C. 50 mL of 0.1M ammonia and 50 mL of 0.05M nitric acid

D. 50 mL of 0.1 M sodium chloride and 50 mL of 0.1M sodium acetate

E. 50 mL of 0.05M sodium hydroxide and 50 mL of 0.1M nitric acid

A buffer is a solution of

a. a weak acid and its base (salt).
b. a weak base and its acid(salt).
Acetic acid/sodium acetate
NH3 and NH4Cl

A. 50 mL of 0.05M sodium hydroxide and 50 mL of 0.1M nitrous acid

For example, your first problem.
First, write the equation, then set up an ICE chart.
NaOH + HNO2 ==> NaNO2 + H2O
2.5....5.0...... 0.......0 initial
-2.5...-2.5......+2.5....+2.5 change
0......2.5.......2.5.....2.5 final

The table with the equation comes from the following data:
mmoles NaOH = 50 x 0.05 = 2.5 mmoles.
mmoles HNO2 = 50 x 0.1 = 5 mmoles.

From the final solution, you can see you have some HNO2 and its salt; that is a weak acid and its salt. Therefore, this is a buffered solution.

abcd

A & D

To determine which solutions will act as a buffer, we need to identify pairs of solutions that consist of a weak acid and its conjugate base or a weak base and its conjugate acid.

A buffer is a solution that can resist changes in pH when small amounts of an acid or base are added to it. It is composed of a weak acid and its conjugate base or a weak base and its conjugate acid.

Let's analyze each option:

A. 50 mL of 0.05M sodium hydroxide and 50 mL of 0.1M nitrous acid
- Sodium hydroxide (NaOH) is a strong base, and nitrous acid (HNO2) is a weak acid. This pair is not a buffer.

B. 50 mL of 0.1M ammonia and 50 mL of 0.1M ammonium acetate
- Ammonia (NH3) is a weak base, and ammonium acetate (NH4OAc) is the conjugate acid of the weak base ammonia. This pair is a buffer.

C. 50 mL of 0.1M ammonia and 50 mL of 0.05M nitric acid
- Ammonia (NH3) is a weak base, but nitric acid (HNO3) is a strong acid. This pair is not a buffer.

D. 50 mL of 0.1 M sodium chloride and 50 mL of 0.1M sodium acetate
- Both sodium chloride (NaCl) and sodium acetate (CH3COONa) are strong electrolytes, not a weak acid-base pair. This pair is not a buffer.

E. 50 mL of 0.05M sodium hydroxide and 50 mL of 0.1M nitric acid
- Sodium hydroxide (NaOH) is a strong base, and nitric acid (HNO3) is a strong acid. This pair is not a buffer.

Therefore, the only pair of solutions that act as a buffer is option B: 50 mL of 0.1M ammonia and 50 mL of 0.1M ammonium acetate.