Question

Which of the following is not a combination reaction
(a) Reaction of hydrogen with nitrogen
(b) Reaction of quicklime with water
(c) Combustion of magnesium in air
(d) Heating of limestone ​

Answer 1

Answer:

reaction of hydrogen with nitrogen

Answer 2

(d) Heating of Limestone is not a combination reaction.

Explanation for the answer:

• A reaction in which two or more reactants combine to form a single product is known as Combination reaction.
• When Limestone is heated strongly, it starts decomposing to form calcium oxide and carbon dioxide.
• Hence, it is a Decomposition reaction.
• A reaction in which a single compound breaks down into two or more new compounds is known as Decomposition reaction.
• Hence, the correct answer among all the options is option (d) Heating of limestone.

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