Predict whether the following solutions are acidic basic or neutral. Provide explanations to support your predictions a) ammonium phosphate b) Ammonium sulfate c) Magnesium oxide
a. Which is stronger, Kb for NH3 or Ka for H3PO4.
b. Which is stronger, Kb for NH3 or Ka for H2SO4.
c. MgO + H2O ==> Mg(OH)2
Both a and b will be acidic or basic depending upon the strength of Ka or Kb. c is a hydroxide so it will be basic.
To predict whether a solution is acidic, basic, or neutral, we need to understand the properties of the compounds involved. Let's analyze each compound and determine the nature of their solutions:
a) Ammonium phosphate (NH4)3PO4:
Ammonium phosphate is composed of ammonium ions (NH4⁺) and phosphate ions (PO4³⁻). The ammonium ion can behave as an acidic ion, whereas the phosphate ion can behave as a basic ion. When these ions are dissolved in water, the acidic nature of the ammonium ion will dominate, making the solution acidic.
Explanation: In this case, the presence of ammonium ions will increase the concentration of H⁺ ions in the solution, effectively making it acidic.
b) Ammonium sulfate (NH4)2SO4:
Ammonium sulfate is composed of ammonium ions (NH4⁺) and sulfate ions (SO4²⁻). Similar to ammonium phosphate, the ammonium ion behaves as an acidic ion. However, the sulfate ion is neither acidic nor basic. Therefore, the solution will still be acidic due to the presence of the ammonium ion.
Explanation: The excess of ammonium ions will lead to an increase in H⁺ concentration, resulting in an acidic solution.
c) Magnesium oxide (MgO):
Magnesium oxide consists of magnesium ions (Mg²⁺) and oxide ions (O²⁻). None of these ions behave as acidic or basic ions. Therefore, when dissolved in water, magnesium oxide forms a neutral solution.
Explanation: Since there are no acidic or basic ions present, the solution will not have an excess of H⁺ or OH⁻ ions, making it neutral.
To summarize:
a) Ammonium phosphate: Acidic solution (due to the presence of ammonium ions)
b) Ammonium sulfate: Acidic solution (due to the presence of ammonium ions)
c) Magnesium oxide: Neutral solution (no acidic or basic ions present)