'रासायनिक अभिक्रिया' (chemical reaction) होने के संकेत हैं:

उत्तर: (D) Color change, gas evolution, temperature change, precipitate formation — Evidence of chemical reaction: color change (iron rusting), gas bubbles (acid + metal), temperature change (exo/endothermic), precipitate (insoluble solid forms), change in smell. Physical change: no ...