H$^+$ + OH$^-$ → H$_2$O The equation above illustrates

Analysis

The question asks you to identify the chemical process represented by the ionic equation: H$^+$ + OH$^-$ → H$_2$O

Concept Explanation

This equation represents the fundamental reaction between an acid and a base.

• H$^+$ ions are the characteristic ions provided by acids in an aqueous solution.
• OH$^-$ ions are the characteristic ions provided by bases (alkalis) in an aqueous solution.
• When these two ions combine, they form water (H$_2$O), which is a neutral molecule.

This specific reaction is the core of a neutralization reaction, where an acid and a base react to form salt and water. Even when other spectator ions (like Na$^+$ or Cl$^-$) are present in the full chemical equation (e.g., HCl + NaOH → NaCl + H$_2$O), this ionic equation remains the same because it shows the actual chemical change occurring.

Step-by-Step Solution

1. Examine the reactants: We have a hydrogen ion (acidic) and a hydroxide ion (basic).
2. Examine the product: The product is water, which has a pH of 7 (neutral).
3. Evaluate the options: • Precipitation: Involves the formation of an insoluble solid from a solution. This is not happening here. • Hydration: Involves the addition of water to a substance. This is not the case here. • Hydrolysis: Involves the reaction of a substance with water to break it down. This is the reverse of this process. • Neutralization: This is the reaction between an acid and a base to produce salt and water. Since H$^+$ and OH$^-$ are the active components of acids and bases respectively, their combination is the definition of neutralization.

Conclusion

The reaction H$^+$ + OH$^-$ → H$_2$O is the net ionic equation for the neutralization of a strong acid by a strong base.

Exam Tip

Whenever you see a question involving H$^+$ and OH$^-$ reacting to form water, always look for "Neutralization" as your first choice. It is a classic JAMB question that tests your understanding of ionic equations!