Given the following solutions:

1. (a) 0.1 M NH₃
2. (b) 0.1 M Na₂CO₃
3. (c) 0.1 M NaCl
4. (d) 0.1 M CH₃CO₂H
5. (e) 0.1 M NH₄Cl
6. (f) 0.l MNH₄CH₃CO₂
7. (g) 0.1 M NH₄CH₃CO₂
   1. (i) Which of the solutions are acidic?
   2. (ii) Which of the solutions are basic?
   3. (iii) Which of the solutions is most acidic?

Interpretation:

a) 0.1M NH3b) 0.1M Na2CO3c) 0.1M NaCld) 0.1M CH3CO2H

e) 0.1M NH4Clf) 0.1M NaCH3CO2g) 0.1M ​NH4CH3CO2

The solutions which are acidic have to be determined from the solutions given above.

Concept introduction:

• Salts are solid particles that are composed of cations and anions. When these are dissolved in water may or may not alter the pH of a solution due to the cation, anion or both.
• Salts of cations from strong bases and anions of strong acids have no effect of the pH of an aqueous solution.

    The solution pH is equal to the 7.

    Example:

            NaCl(aq), KCl(aq), NaI(aq), NaNO3(aq)

• The salt of a weak base (Cation) and strong acid (anion) dissolves in water to form acidic solutions.

  The solution has a pH less than 7.

• The slat of strong base (cation) and weak acid (anion) dissolves in water to form basic solutions.

  The solution has a pH is greater than 7.

0.1M CH3CO2H

CH3CO2H is a weak acid. It donates protons to water to form hydronium ions. Therefore, the solution is acidic.

CH3CO2H(aq) + H2O(l)⇌CH3CO2-(aq) + H3O+(aq)Ka=1.8×10-5

0.01M NH4Cl

NH4Cl is a salt of a strong acid and weak base

Interpretation:

a) 0.1M NH3b) 0.1M Na2CO3c) 0.1M NaCld) 0.1M CH3CO2H

e) 0.1M NH4Clf) 0.1M NaCH3CO2g) 0.1M ​NH4CH3CO2

The solutions which are basic have to be determined from the solutions given above.

Concept introduction:

• Salts are solid particles that are composed of cations and anions. When these are dissolved in water may or may not alter the pH of a solution due to the cation, anion or both.
• Salts of cations from strong bases and anions of strong acids have no effect of the pH of an aqueous solution.

    The solution pH is equal to the 7.

    Example:

            NaCl(aq), KCl(aq), NaI(aq), NaNO3(aq)

• The salt of a weak base (Cation) and strong acid (anion) dissolves in water to form acidic solutions.

  The solution has a pH less than 7.

• The slat of strong base (cation) and weak acid (anion) dissolves in water to form basic solutions.

  The solution has a pH is greater than 7.

Interpretation:

a) 0.1M NH3b) 0.1M Na2CO3c) 0.1M NaCld) 0.1M CH3CO2H

e) 0.1M NH4Clf) 0.1M NaCH3CO2g) 0.1M ​NH4CH3CO2

The solution which is the most acidic from the solutions given above has to be determined.

Concept introduction:

• Salts are solid particles that are composed of cations and anions. When these are dissolved in water may or may not alter the pH of a solution due to the cation, anion or both.
• Salts of cations from strong bases and anions of strong acids have no effect of the pH of an aqueous solution.

    The solution pH is equal to the 7.

    Example:

            NaCl(aq), KCl(aq), NaI(aq), NaNO3(aq)

• The salt of a weak base (Cation) and strong acid (anion) dissolves in water to form acidic solutions.

  The solution has a pH less than 7.

• The slat of strong base (cation) and weak acid (anion) dissolves in water to form basic solutions.

  The solution has a pH is greater than 7.