When dilute HCl reacts with zinc granules, bubbles of hydrogen gas are released, showing effervescence. Also, zinc chloride solution forms. These two observable changes confirm that a new substance is formed, proving chemical change.
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When dilute hydrochloric acid reacts with zinc granules, effervescence occurs due to the release of hydrogen gas, which can be tested by a pop sound. Additionally, zinc chloride solution is formed, different from the original reactants. The formation of new substances and energy release confirm that a chemical change has occurred, supported by both visible gas evolution and compound formation.