Question

Assertion(A): The mass of the nickel catalyst recovered after being used, the hydrogenation of an oil is less than the mass of nickel added to the reaction.
Reason(R): Catalysts take part in the reaction but are recovered in the end.
A.If both (A) and (R) are true and (R) is the correct explanation of (A).
B.If both (A) and (R) are true but (R) is not the correct explanation of (A).
C.If (A) is correct but (R) is incorrect.
D.If (A) is incorrect and (R) is correct.

Answer 1

Hint: To answer this question, you should recall the concept of catalysts. It can be defined as a substance that changes the reaction rate by changing the path of reaction. Use the knowledge of reactivity of a catalyst to answer the question.

Complete answer:
Catalyst is a very usual word that comes up in the topic of chemical reactions. This is where a catalyst comes in. Generally, a catalyst speeds up and increases the reaction rate. Catalysts break or rebuild the chemical bonds between the atoms which are present in the molecules of different elements or compounds. Catalysts make the whole reaction process easier and efficient.
Key points of a catalyst are that it does not initiate a chemical reaction. It cannot be consumed in the reaction. It forms intermediates with reactants and at the same time facilitates the production of the final reaction product. As the amount of catalyst does not change in the reaction the assertion is incorrect and reason is correct.

Therefore, the correct answer is option (D).

Note:
There are four types of catalysts:
1.Positive Catalysts: Catalysts which 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.
2.Negative Catalysts: Catalysts which decrease the rate of reaction and negative catalyst.
3.Promoter or Accelerators: A substance which increases the catalyst activity are known as Promoters or accelerators.
4.Catalyst Poisons or Inhibitors: Substances which decrease the catalyst activity are known as catalyst poisons or inhibitors.