Question

What is a positive catalyst and negative catalyst?
why are they added to any chemical reaction?​

Answer 1

If a catalyst enhance the rate of a reaction, is known as positive catalyst and if it retards the rate then it is known as negative catalyst.

Catalysts that increase the rate of a chemical reaction are positive catalysts. It increases the rate of reaction by lowering the activation energy barriers such that a large number of reaction molecules are converted into products, thereby the percentage of yield of products increases.

- The catalyst which decreases the rate of reaction is known as inhibitor or negative catalyst and the process is known as negative catalysis or inhibition. Negative catalysts are useful to slow down or stop any unwanted reactions

Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products.

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Answer 2

Answer:

Every chemical reaction has a specific rate, some reactions occur fast, like the reaction of sodium with water, whereas some reactions occur very slowly, like the rusting of iron. Catalysts are these substances which when added in the reaction changes the rate of the reaction, it can either make it fast or slow. However, the catalyst itself does not get consumed as the reaction proceeds. Catalysts exist in solid, liquid as well as gaseous forms.

Catalysts also change the activation energy of the reaction. Positive catalysts are those catalysts which increase the rate of the reaction This means that the activation energy of the reaction is lowered, and the speed of the reaction also increases. An example of positive catalysis is decomposition of potassium chlorate. Without a catalyst, decomposition takes place at 7000C, and with an MnO catalyst, decomposition takes.

Negative catalysts are opposite of the positive catalysts. They decrease the overall rate of the chemical reaction. An example of a negative catalyst is phosphoric acid, which can be used to decrease the rate of hydrogen peroxide decomposition.

H2O2−→−−−H3PO4H2O+O2

Catalysts create an alternative path for the reaction to occur, hence they are responsible for changing reaction rates.