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Question
State four conditions necessary for a chemical reaction to take place.
Solution
Ans: Close contact— For a chemical reaction to take place the reactants should be brought in close contact i.e., they should be mixed,
\[\ce{Sodium + Water -> Sodium hydroxide + Water}\]
Solution form— Some substances react with each other only when they are mixed in the solution form, e.g.,
\[\ce{\underset{\text{(aq.)}}{Silver nitrate} + \underset{\text{(aq.)}}{Sodium chloride} ->\underset{\text{(ppt.)}}{Silver nitrate}+\underset{\text{(aq.)}}{Sodium nitrate}}\]
Heat— Some reactants need to be heated to undergo a chemical change, e.g.,
\[\ce{Potassium chlorate->[heat] Potassium chloride + oxygen}\]
Light— Some reactions take place in the presence of light.
\[\ce{Carbon dioxide + Water ->[chlrophyll][sunlight] Glucose + Oxygen}\]
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