Question

Write a chemical equation for the neutralization of acetic acid with aqueous sodium hydroxide to give aqueous sodium acetate plus water.

Short answer

The balanced equation is: \( \text{CH}_3\text{COOH} + \text{NaOH} \rightarrow \text{CH}_3\text{COONa} + \text{H}_2\text{O} \).

Step-by-step solution

Identify Reactants and Products

Identify the chemical formulas for each substance in the problem. Acetic acid is represented as \( \text{CH}_3\text{COOH} \), sodium hydroxide as \( \text{NaOH} \), sodium acetate as \( \text{CH}_3\text{COONa} \), and water as \( \text{H}_2\text{O} \).

Write the Reactants

Start writing the chemical equation by placing the reactants on the left side: \( \text{CH}_3\text{COOH} \) (acetic acid) and \( \text{NaOH} \) (sodium hydroxide).

Write the Products

Place the products on the right side of the equation. The products are \( \text{CH}_3\text{COONa} \) (sodium acetate) and \( \text{H}_2\text{O} \) (water).

Balance the Equation

Ensure the number of atoms of each element is equal on both sides of the equation. For this neutralization reaction, it's already balanced as written: \[ \text{CH}_3\text{COOH} + \text{NaOH} \rightarrow \text{CH}_3\text{COONa} + \text{H}_2\text{O} \].

Key concepts

Chemical Equation

A chemical equation is a concise way to express what happens in a chemical reaction. In a chemical equation, you see the reactants and the products. Reactants are substances you start with, and they are located on the left side of the equation. Products are new substances formed, and these are shown on the right side.
The arrow in a chemical equation points from reactants to products, indicating the direction of the reaction. It can also suggest that reactants yield products.

• Balance is key in a chemical equation. This means the number of each type of atom on the reactant side should match the number on the product side.
• Subscripts indicate how many atoms of an element are in a molecule (like the 3 in \( \text{CH}_3\text{COOH} \)).
• Coefficients, placed in front of formulas, tell us how many molecules are involved. A lack of a coefficient means there's just one molecule.

For reactions like that of acetic acid with sodium hydroxide, the balancing is straightforward since it is often balanced as written. Understanding chemical equations helps in predicting the outcomes of reactions.

Acetic Acid

Acetic acid is a common carboxylic acid, represented by the formula \( \text{CH}_3\text{COOH} \). It is the primary component of vinegar, imparting its characteristic sour taste and acidic smell.
Acetic acid is a weak acid, meaning it does not completely dissociate in water. Instead, it partially ionizes, forming a mixture of acetic acid molecules and ions in solution. This can be shown by:

• \( \text{CH}_3\text{COOH (aq)} \rightleftharpoons \text{CH}_3\text{COO}^- (aq) + \text{H}^+ (aq) \)

In the reaction with sodium hydroxide, acetic acid donates its hydrogen ion \( \text{H}^+ \) to the hydroxide ion \( \text{OH}^- \) from sodium hydroxide. This results in the formation of water and sodium acetate. This process is part of what defines neutralization, where an acid and a base react to form water and a salt.

Sodium Hydroxide

Sodium hydroxide (\( \text{NaOH} \)) is a strong base. It is also known as lye or caustic soda. As a strong base, it dissociates completely in water, producing sodium ions \( \text{Na}^+ \) and hydroxide ions \( \text{OH}^- \).
Bases like sodium hydroxide have the ability to neutralize acids. They do so by reacting with hydrogen ions \( \text{H}^+ \) to form water:

• \( \text{OH}^- + \text{H}^+ \rightarrow \text{H}_2\text{O} \)

In a neutralization reaction with acetic acid, sodium hydroxide leads to the production of water and sodium acetate (\( \text{CH}_3\text{COONa} \)). This kind of reaction tends toward equilibrium, meaning that the forward reaction (creating products) and the reverse reaction (reforming reactants) occur at the same rate once equilibrium is reached. Sodium hydroxide's complete dissociation in water ensures the reaction proceeds efficiently.