Question

state why addition of sodium chloride to water is considered a physical change ,while addition of dilute sulfuric acid to zinc is considered a chemical change

Answer 1

Answer:

Addition of NaCl is physical change because on evaporation of water the NaCl can recollect( the reaction is reversible). But in reaction of H2SO4 and zinc ,zinc forms ZnSO4 which cannot be reversed ( the change is permanent) . Hence it is chemical change.