Sodium hydroxide (NaOH) is a strong base, and when it dissolves in water, it undergoes a chemical reaction with water molecules to form sodium ions (Na+) and hydroxide ions (OH-). This reaction is represented by the following chemical equation:
NaOH + H2O -> Na+ + OH-
In this reaction, the chemical bonds between the sodium and hydroxide atoms in sodium hydroxide are broken, and new chemical bonds are formed between the sodium atoms and the oxygen atoms in water, and between the hydroxide atoms and the hydrogen atoms in water. As a result of this chemical reaction, the properties of the substance change. Sodium hydroxide is a solid at room temperature, while the solution formed by dissolving sodium hydroxide in water is a liquid. The solution also has a basic pH, due to the presence of hydroxide ions.
Therefore, dissolving sodium hydroxide in water is a chemical change because it involves the breaking and formation of chemical bonds, and a change in the properties of the substance.
