Question

Which of the following reaction is endothermic reaction:-
(1) Bond formation by two unstable atoms at certain condition
(2) Combustion reactions
(3) Conversion of more stable allotrope to less stable allotropic element
(4) Condensation of vapour to its liquid state​

Answer 1

Answer:

2) combustion reactions

Explanation:

Combustion reaction requires heat and oxygen

as we have to give heat that means its endothermic reaction

rest all the above reactions release heat hence they are endothermic

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Answer 2

Answer:

3. Conversation of more stable allotrope to less stable allotrope element

Explanation:

Options 1,2, and 4 is found to be an exothermic reaction because this process will lose its energy in the form of heat

Option 3. will take place when a certain amount of heat is being supplied. Therefore it is an endothermic reaction and Hence it is a correct option.