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प्रश्न
What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.
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उत्तर
(i) Positive catalyst: When a catalyst increases the rate of chemical reaction, it is called positive catalyst.
e.g. when potassium chlorate heated to 700°C decomposes to evolve oxygen gas, when MnO2is added the decomposition takes place at 300°C
\[\ce{2KCIO3->[MnO2][300°C] 2KCl + 3O2}\]
(ii) Negative catalyst: When a catalyst decreases the rate of chemical reaction it is called negative catalyst.
Example. Phosphoric acid acts as a negative catalyst to decrease the rate of the decomposition of hydrogen peroxide. Alcohol too acts as a negative catalyst in certain chemical reactions.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
heat.
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| BaCl2(aq) + ZnSO4(aq) | H2CO3(aq) | Displacement |
| 2AgCl(s) | FeSO4(aq) + Cu(s) | Combination |
| CuSO4(aq) + Fe(s) | BaSO4↓ + ZnCl2(aq) | Decomposition |
| H2O(l) + CO2(g) | 2Ag(s) + Cl2(g) | Double displacement |
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Reason (R): Physical changes are always reversible.
