Which one among the following is an example of chemical change ?

A chemical change involves a process where one or more substances are altered into one or more new and different substances through the breaking and forming of chemical bonds. Option D is a classic example of a chemical change known as a neutralization reaction.

• When Sodium Hydroxide (NaOH), a base, is mixed with Hydrochloric Acid (HCl), an acid, they react to form Sodium Chloride (NaCl) and Water (H2O). The chemical identity of the reactants is permanently altered.
• Sublimation of camphor and melting of ice (Options A and B) are phase changes (physical changes) where the substance's state changes but its chemical composition remains the same.
• Heating an iron rod (Option C) is a physical change as it involves a change in temperature or volume (thermal expansion) without forming a new chemical substance.