Class 10 // Chemistry// Chapter 1// Chemical reaction and Equation// Full explain (NCERT) . . . . Here's a clear and concise *description* of *Class 10 Science Chapter 1: Chemical Reactions and Equations* as per the NCERT syllabus: --- *Chapter 1: Chemical Reactions and Equations – Description* This chapter introduces students to the fundamental concepts of chemical reactions and the symbolic representation of these reactions using chemical equations. #### *Key Concepts:* 1. *Chemical Reactions:* A chemical reaction is a process in which one or more substances (reactants) are transformed into new substances (products). Indicators of a chemical reaction include change in color, temperature, formation of gas, precipitate, or change in state. 2. *Chemical Equations:* A *chemical equation* is a symbolic representation of a chemical reaction. Example: $$ \text{H}_2 + \text{O}_2 \rightarrow \text{H}_2\text{O} $$ This represents hydrogen reacting with oxygen to form water. 3. *Balancing Chemical Equations:* Law of Conservation of Mass: Mass can neither be created nor destroyed in a chemical reaction. Chemical equations must be *balanced* so that the number of atoms of each element is equal on both sides of the equation. 4. *Types of Chemical Reactions:* **Combination Reaction**: Two or more substances combine to form a single product. Example: $\text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2$ **Decomposition Reaction**: A compound breaks down into two or more simpler substances. Example: $\text{2H}_2\text{O} \rightarrow 2\text{H}_2 + \text{O}_2$ **Displacement Reaction**: A more reactive element displaces a less reactive element. Example: $\text{Zn} + \text{CuSO}_4 \rightarrow \text{ZnSO}_4 + \text{Cu}$ **Double Displacement Reaction**: Exchange of ions between two compounds. Example: $\text{Na}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + \text{2NaCl}$ **Redox Reactions**: Reactions involving oxidation and reduction processes. 5. *Oxidation and Reduction:* **Oxidation**: Addition of oxygen or removal of hydrogen. **Reduction**: Removal of oxygen or addition of hydrogen. These often occur together in redox reactions. 6. *Effects of Oxidation in Everyday Life:* **Corrosion**: The gradual destruction of metals (e.g., rusting of iron). **Rancidity**: Spoiling of food due to oxidation (e.g., oil turning bad).