Question

Consider the following system composed of five 1 M aqueous solutions; iron (II) chloride, sodium sulfite, sulfuric acid, silver nitrate, and sodium hydroxide.

Yoou will mix the solutions in a pair wise fashion so that all possible reactions between the solutions are tested. Use the solubility rules to predict when the precipitation reaction will occur. For each combination that produces a precipitation reaction write a balanced molecular equation and a net ionic equation. Indicate all phases in your equations.

The combination of sodium sulfite and sulfuric acid does not produce a precipitate but does produce a foul smelling gas, sulfur dioxide, and molecular water. Write a balanced molecular equation and a net ionic equation for the reaction. Indicate all phases in your equations.

One combination of chemical above does not produce a precipitate or a gas but you notice the test tube warms up significantly upon mixing. This is due to the high heat of neutralization. Identify the pair that produces a neutralization reaction and write a balanced molecular equation and a net ionic equation. Indicate all phases in your equations.

Answer 1

Combination of Na₂SO₃ + H₂SO₄

2Na⁺ + SO₃^-2 + 2H⁺ + SO₄^-2 -> Na₂SO₄ + SO₂ + H₂O

Na₂SO₃ + H₂SO₄ -> Na₂SO₄ + SO₂ + H₂O

Combination of NaOH + H₂SO₄

2Na⁺ + 2OH^- + 2H⁺ + SO₄^-2 -> Na₂SO₄ +2H₂O

2NaOH + H₂SO₄ -> Na₂SO₄ +2H₂O + heat

Precipitates (following solubility rules, given that all hydroxides are insoluble and all sulfates are soluble except those of silver, mercury, lead, barium and calcium):

1) FeCl₂ + 2NaOH -> Fe⁺² + 2Cl^- + Na⁺ + OH^- -> 2NaCl + Fe(OH)₂ (s)

2) Na₂SO₃ + 2AgNO₃ -> 2Na⁺ + SO₃^-2 + Ag⁺ + NO3^- -> 2NaNO₃ + Ag₂SO₃ (s)

3) H₂SO₄ + 2AgNO₃ -> 2H⁺ + SO₄^-2 + Ag⁺ + NO3^- -> 2HNO₃ + Ag₂SO₄ (s)