Problem 95 - Chemistry Matter and Change

Question

Write the net ionic equation for a chemical reaction that occurs in an aqueous solution and produces water.

Step-by-Step Solution

Answer

The net ionic equation for the reaction between hydrochloric acid and sodium hydroxide in an aqueous solution that produces water is: \(H^+(aq) + OH^-(aq) → H_2O(l)\)

Step 1: Choose a reaction that occurs in an aqueous solution and produces water

Let's consider the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH), which is an example of an acid-base reaction that occurs in an aqueous solution and produces water.

Step 2: Write the complete balanced molecular equation for the chosen reaction

The balanced molecular equation for the reaction between hydrochloric acid and sodium hydroxide is: HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

Step 3: Convert the complete molecular equation into a total ionic equation

The total ionic equation is found by breaking all the soluble ionic compounds into their respective ions: \(H^+(aq) + Cl^-(aq) + Na^+(aq) + OH^-(aq) → Na^+(aq) + Cl^-(aq) + H_2O(l)\)

Step 4: Cancel out spectator ions to get the net ionic equation

Spectator ions are ions that don't participate in the reaction and appear in the same form on both sides of the equation. In this case, the sodium ion (Na⁺) and the chloride ion (Cl⁻) are spectator ions. We cancel them out: \(H^+(aq) + OH^-(aq) → H_2O(l)\) The net ionic equation for the reaction between hydrochloric acid and sodium hydroxide in an aqueous solution that produces water is: \(H^+(aq) + OH^-(aq) → H_2O(l)\)

Key Concepts

Acid-Base Reactions

Understanding acid-base reactions is vital for students beginning to dive into the world of aqueous solution chemistry. This particular type of reaction involves the transfer of protons (H⁺ ions) from an acid to a base. When acids and bases react, they form water (H₂O) and an ionic compound, commonly referred to as a salt. A classic example of an acid-base reaction is the neutralization between hydrochloric acid (HCl) and sodium hydroxide (NaOH), where water and sodium chloride (NaCl) are the products.

In terms of molecular interactions, an acid donates a proton whereas a base accepts it. Following the Bronsted-Lowry definition, the aqueous solution of HCl (acid) releases H⁺ ions, and the solution of NaOH (base) provides OH^- ions, which then combine to form water. This specific interaction is what drives the net ionic equation we aim to understand.

Spectator Ions

While exploring ionic equations, it's crucial to identify the players actively involved in the chemical reaction and those just 'watching' the reaction happen. These non-participants are known as spectator ions. They remain unchanged and do not contribute to the overall reaction.

In our example with hydrochloric acid and sodium hydroxide, the spectator ions are Na⁺ and Cl^-. They appear unchanged on both the reactant and the product sides of our equation. When writing the net ionic equation, we omit these spectators to focus solely on the chemical change occurring. It's like highlighting only the parts of the equation that are engaging in action, hence getting down to the essence of the reaction which, in our case, is simply the formation of water.

Aqueous Solution Chemistry

Delving into aqueous solution chemistry means understanding the behavior of substances dissolved in water. The term 'aqueous' (aq) indicates that a substance is dissolved in water. In our hydrochloric acid and sodium hydroxide reaction, both are soluble in water, disassociating into their respective ions.

The nature of the solute-solvent interaction in aqueous solutions is key to predicting the outcome of reactions. Water's polar nature allows it to separate ionic compounds into ions, which can then freely move and react. This freedom is essential in allowing the acid-base neutralization to occur, leading to the formation of both a salt and water. A strong comprehension of how substances interact in aqueous solutions can greatly assist in predicting the products of such reactions, which is an invaluable skill in the study of chemistry.