While balancing a chemical equation, only the coefficients of the formulae are changed, but the subscripts are not changed. Give reasons.

Explanation

**Step-by-Step Solution:**

1. **Understanding Chemical Equations**: A chemical equation represents a chemical reaction using symbols and formulas to denote the reactants and products involved. For example, in the reaction \( N_2 + H_2 \rightarrow NH_3 \), \( N_2 \) and \( H_2 \) are the reactants, while \( NH_3 \) is the product.

2. **Role of Coefficients and Subscripts**: In a chemical formula, the subscripts indicate the number of atoms of each element in a molecule. For instance, in \( H_2O \), the subscript '2' indicates there are two hydrogen atoms. Coefficients, on the other hand, indicate the number of molecules or moles of a substance involved in the reaction.

3. **Balancing the Equation**: When balancing a chemical equation, we adjust the coefficients to ensure that the number of atoms of each element is the same on both sides of the equation. For example, to balance the equation \( N_2 + H_2 \rightarrow NH_3 \), we might find that we need to change the coefficients to \( 1N_2 + 3H_2 \rightarrow 2NH_3 \).

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