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प्रश्न
How do the following help in bringing about a chemical change?
catalyst .
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उत्तर
A catalyst can either increases or decreases the rate of chemical reaction and some chemical reactions need a catalyst to change the rate of the reaction, in case it is too slow or too fast
1. Positive catalyst: When a catalyst increase the rate of reaction finely divided iron is used as a positive catalyst in the manufacturing of ammonia from hydrogen and nitrogen.
\[\ce{N2 + 3H2 ⇌[Iron (Catalyst) 200-900][450°C] 2NH3 + Heat}\]
2. Negative Catalyst: When a catalyst decreases the rate of reaction.
Ex. Phosphoric acid act as a negative catalyst to decrease the rate of the decomposition of hydrogen peroxide.
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