Which one among the following is an example of chemical change ?
[amp_mcq option1=”Sublimation of camphor” option2=”Melting of ice” option3=”Heating of an iron rod” option4=”Mixing of NaOH and HCl” correct=”option4″]
This question was previously asked in
UPSC NDA-2 – 2024
A chemical change results in the formation of new substances with different chemical properties. Mixing sodium hydroxide (NaOH, a strong base) and hydrochloric acid (HCl, a strong acid) causes a neutralization reaction: NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l). Sodium chloride (NaCl) and water (H₂O) are produced, which have entirely different chemical properties compared to the reactants. Sublimation, melting, and simple heating of a solid are physical changes, altering the state or temperature but not the chemical identity of the substance.
Chemical changes involve the breaking and forming of chemical bonds, resulting in new substances. Physical changes involve alterations in form, state, or appearance without changing chemical composition.