Question

What is meant by neutralization? Give some examples identifying spectator ions in the reactions.

Short answer

Answer: Spectator ions are ions that remain unchanged during a chemical reaction and do not actively participate in the reaction. They can be identified in neutralization reactions by determining the ions that are the same on both sides of the reaction. In other words, spectator ions appear in both the reactants and products without any change in their charge or form.

Step-by-step solution

1. Neutralization Reaction Definition

A neutralization reaction is a chemical reaction between an acid and a base, resulting in the formation of water (H2O) and a salt. This reaction results in the acid donating a proton (H+) to the base, and the base providing a hydroxide ion (OH-). The reaction is usually represented as: Acid + Base → Salt + Water

2. Examples of Neutralization Reactions

Here are some examples of neutralization reactions: (a) Hydrochloric Acid (HCl) + Sodium Hydroxide (NaOH) → Sodium Chloride (NaCl) + Water (H2O) In this reaction, HCl donates a proton (H+) to NaOH, forming the salt NaCl and water. (b) Sulfuric Acid (H2SO4) + Potassium Hydroxide (KOH) → Potassium Sulfate (K2SO4) + Water (2H2O) In this example, H2SO4 donates two protons to KOH and results in the formation of K2SO4 and water. (c) Nitric Acid (HNO3) + Calcium Hydroxide (Ca(OH)2) → Calcium Nitrate (Ca(NO3)2) + Water (2H2O) Here, HNO3 donates a proton to Ca(OH)2 to form the salt Ca(NO3)2 and water.

3. Identifying Spectator Ions in Neutralization Reactions

Spectator ions are the ions that remain unchanged during the reaction and do not participate actively in the reaction. They can be found by identifying the ions that are the same on both sides of the reaction. (a) HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l) The reaction can be written in terms of ions: H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) → Na+(aq) + Cl-(aq) + H2O (l) In this case, the spectator ions are Na+ and Cl-, as they remain unchanged in the product. (b) 2H2SO4 (aq) + 2KOH (aq) → K2SO4 (aq) + 4H2O (l) Ions in the reaction: 2H+(aq) + 2SO4^(2-)(aq) + 2K+(aq) + 2OH-(aq) → 2K+(aq) + 2SO4^(2-)(aq) + 4H2O (l) The spectator ions in this reaction are K+ and SO4^(2-) as they are present on both sides of the reaction without any change. (c) 2HNO3 (aq) + Ca(OH)2 (aq) → Ca(NO3)2 (aq) + 2H2O (l) Ions in the reaction: 2H+(aq) + 2NO3^(-)(aq) + Ca^(2+)(aq) + 2OH^(-)(aq) → Ca^(2+)(aq) + 2NO3^(-)(aq) + 2H2O (l) In this example, the spectator ions are Ca^(2+) and NO3^(-) as they remain unchanged throughout the reaction.