Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Neutralization is a chemical reaction where an acid reacts with an alkali (a soluble base) to produce a salt and water. The general word equation is: .
In terms of , an acid has a and an alkali has a . When they neutralize each other completely, the resulting solution has a of (neutral).
The reaction involves the hydrogen ions () from the acid reacting with the hydroxide ions () from the alkali to form water molecules ().
The name of the salt produced depends on the acid used: Hydrochloric acid () produces chlorides, Sulfuric acid () produces sulfates, and Nitric acid () produces nitrates.
Indicators like Universal Indicator can be used to track the reaction; the color will change towards green (neutral) as the acid and alkali are mixed in the correct proportions.
Real-world applications include using antacids () to neutralize excess stomach acid () and using lime () to neutralize acidic soil.
📐Formulae
💡Examples
Problem 1:
Predict the products of the reaction between Hydrochloric acid () and Magnesium hydroxide ().
Solution:
()
Explanation:
The 'Magnesium' part comes from the alkali and the 'chloride' part comes from the Hydrochloric acid. Water is always a byproduct of a neutralization reaction between an acid and a metal hydroxide.
Problem 2:
If a solution of Nitric acid () is added to a solution of Potassium hydroxide () containing Universal Indicator, what color change occurs when neutralization is complete?
Solution:
The color changes from purple/blue (alkaline) to green (neutral).
Explanation:
Potassium hydroxide is an alkali (), so the indicator starts as purple or blue. As acid is added, the drops. At the point of neutralization, the becomes , which corresponds to a green color in Universal Indicator.