Question

Will the following oxides give acidic, basic, or neutral solutions when dissolved in water? Write reactions to justify your answers. a. \(\mathrm{CaO}\) b. \(\mathrm{SO}_{2}\) c. \(\mathrm{Cl}_{2} \mathrm{O}\)

Short answer

In summary, when dissolved in water: a. \(\mathrm{CaO}\) forms a basic solution (\(\mathrm{CaO + H}_{2}\mathrm{O \rightarrow Ca(OH)}_2\)). b. \(\mathrm{SO}_{2}\) forms an acidic solution (\(\mathrm{SO}_{2} + \mathrm{H}_{2}\mathrm{O \rightarrow H}_{2}\mathrm{SO}_{3}\)). c. \(\mathrm{Cl}_{2} \mathrm{O}\) forms an acidic solution (\(\mathrm{Cl}_{2}\mathrm{O + H}_{2}\mathrm{O \rightarrow 2HClO}\)).

Step-by-step solution

Dissociate the oxides and determine their acidity or basicity

Begin by determining if the oxides are acidic, basic, or amphoteric. a. \(\mathrm{CaO}\): Calcium oxide is a metal oxide and generally reacts with water to form a base, so it is a basic oxide. b. \(\mathrm{SO}_{2}\): Sulfur dioxide is a non-metal oxide and usually reacts with water to form an acid, so it is an acidic oxide. c. \(\mathrm{Cl}_{2}\mathrm{O}\): Chlorine dioxide is a non-metal oxide and, like sulfur dioxide, typically reacts with water to form an acid, so it is an acidic oxide.

Write reactions of the oxides with water

Now, we will write the reactions of the oxides with water to show how they form acidic, basic, or neutral solutions. a. For \(\mathrm{CaO}\) (basic oxide): \(\mathrm{CaO(s)} + \mathrm{H}_{2}\mathrm{O(l)} \rightarrow \mathrm{Ca(OH)}_2(aq)\) : Calcium oxide reacts with water to form calcium hydroxide, a basic solution. b. For \(\mathrm{SO}_{2}\) (acidic oxide): \(\mathrm{SO}_{2(g)} + \mathrm{H}_{2}\mathrm{O(l)} \rightarrow \mathrm{H}_{2}\mathrm{SO}_{3(aq)}\): Sulfur dioxide dissolves in water to form sulfurous acid, an acidic solution. c. For \(\mathrm{Cl}_{2}\mathrm{O}\) (acidic oxide): \(\mathrm{Cl}_{2}\mathrm{O(g)} + \mathrm{H}_{2}\mathrm{O(l)} \rightarrow \mathrm{2HClO(aq)}\): Chlorine dioxide dissolves in water to form hypochlorous acid, an acidic solution.

Conclude

Based on the reactions, we can conclude that: a. \(\mathrm{CaO}\) will give a basic solution when dissolved in water. b. \(\mathrm{SO}_{2}\) will give an acidic solution when dissolved in water. c. \(\mathrm{Cl}_{2} \mathrm{O}\) will give an acidic solution when dissolved in water.