Balance the following equations. (d) NO₂ + H₂O → HNO₃ + NO

Balancing chemical equations involves ensuring that the number of atoms of each element is the same on both sides of the equation. This is based on the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. Coefficients are used to adjust the quantities of reactants and products to achieve balance.

Stoichiometry is the study of the quantitative relationships between the amounts of reactants and products in a chemical reaction. It allows chemists to predict how much of each substance is needed or produced in a reaction. Understanding stoichiometry is essential for balancing equations, as it provides the ratios in which substances react and form.

Chemical reactions can be classified into several types, including synthesis, decomposition, single replacement, and double replacement. The reaction in the question involves the formation of nitric acid (HNO3) from nitrogen dioxide (NO2) and water (H2O), which is a type of synthesis reaction. Recognizing the type of reaction helps in predicting the products and understanding the overall process.