Final answer:
FeCl₂ dissociates into Fe²⁺ and 2 Cl⁻, HNO₃ dissociates into H⁺ and NO₃⁻, (NH₄)₂SO₄ dissociates into 2 NH₄⁺ and SO₄²⁻, and Ca(OH)₂ dissociates into Ca²⁺ and 2 OH⁻.
Step-by-step explanation:
In order to determine the ions present in solution upon dissolving each of the given substances in water, we need to look at the chemical formulas and dissociation of these substances.
a) FeCl₂:
FeCl₂ dissociates into Fe²⁺ and 2 Cl⁻ ions upon dissolving in water.
b) HNO₃:
HNO₃ dissociates into H⁺ and NO₃⁻ ions upon dissolving in water.
c) (NH₄)₂SO₄:
(NH₄)₂SO₄ dissociates into 2 NH₄⁺ and SO₄²⁻ ions upon dissolving in water.
d) Ca(OH)₂:
Ca(OH)₂ dissociates into Ca²⁺ and 2 OH⁻ ions upon dissolving in water.