Question

A chemical process in which a substance reacts with oxygen to give off heat is called as:
A)endothermic
B)combustion
C)reduction
D)none of the above

Answer 1

Hint: To solve this question, we should have knowledge about the different types of reactions. An endothermic process is the one where heat is absorbed. A combustion process is basically burning of a compound. A reduction reaction involves the addition of hydrogen to a compound.

Complete step by step answer:
We shall analyse each option with the reaction given in the question to find the answer.
In option A, endothermic reaction is a type of reaction which does not occur spontaneously. It requires extra energy which it receives in the form of heat. In the question, it is given that heat is released. Thus, the reaction given is not an endothermic reaction.
In option B, combustion refers to the burning of a substance. As we know that, for ignition oxygen is required and during the reaction energy is released in the form of heat and light. This is consistent with the reaction that is given in the question, i.e. a substance reacting with oxygen to give heat. Thus, the reaction given is a combustion reaction.
In option C, we know reduction involves the removal of oxygen and addition of hydrogen. This is inconsistent with the question as it involves addition of oxygen to the compound. Thus, the reaction given is not a reduction reaction.
$\therefore $ The correct option is option B, i.e. combustion reaction.

Note: In the question, it is given that heat is released during the reaction. This means that the reaction is also an example of an exothermic reaction. A combustion reaction is also an exothermic reaction.