# AP Class 10 Physical Science Chapter 4 Acids, Bases and Salts

Chapter 4 of class 10 Physical Science Acids, Bases and Salts discusses various reactions of acids and bases. Also, neutralisation of bases by acids and many more interesting activities that we encounter in our day to day life are discussed.

## Differences Between Acids and Bases – Acids vs Bases

 Acid Base Formation of H+ (aq) ions in the solution results in the acidic nature of a substance. Formation of OH– in the solution results in the basic nature of a substance. When acids react with metal carbonates, corresponding salt along with the evolution of carbon dioxide and water is formed. Reaction of base with metals results in the formation of the respective salts and the evolution of hydrogen gas. Acidic solutions in water conduct electricity because they produce hydrogen ions. Basic solutions in water conduct electricity because they produce hydroxide ions. More acidic a solution, lesser will be its pH More basic a solution, the stronger will be a base

In the next section, let us look at a few answered chapter questions, to better understand the concepts discussed in the chapter.

## Chapter 4 Acids, Bases and Salts Questions

1. What is a neutralization reaction? Give two examples.

Neutralisation process is a reaction between an acid and a base resulting in the formation of salt and water.

Example:

$HCl+NaOH\rightarrow NaCl+H_2O$

$HNO_3+KOH\rightarrow KNO_3+H_2O$

1. Why does tooth decay start when the pH of mouth is lower than 5.5?