# What Are (I) Positive Catalysts and (Ii) Negative Catalysts? Support Your Answer with One Example for Each of Them. - Chemistry

Short Note

What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.

#### Solution

(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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#### APPEARS IN

Selina Concise Chemistry Class 8 ICSE
Chapter 6 Chemical Reactions
Exercise 1 | Q 4.2 | Page 73