When two intermediate chemical equations are combined, the same substance that appears in the same phase can be canceled out, provided that

Ait is a reactant in one intermediate reaction and a catalyst in the other reaction.
Bit is a product in one intermediate reaction and a catalyst in the other reaction.
Cit is a reactant in one intermediate reaction and a product in the other reaction.
Dit is a reactant in both of the intermediate reactions.

The correct answer in here is it is a reactant in one intermediate reaction and a product in the other reaction. So your option is C. This one explains itself perfectly. I hope this can help you a lot

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RomeliaThurston RomeliaThurston · Answer 2 · 2019-05-13T04:45:55-04:00

Answer: The correct answer is Option C.

Explanation:

When two intermediate chemical equations combine, the same substance which appears in the same phase on the reactant side can be cancelled out only when it also appears in the same phase on the product side.

For example: The conversion of diamond to graphite follows two intermediate steps, which are written as:

\(C(s)_{diamond}+O_2(g)\rightarrow CO_2(g)\)

\(CO_2(g)\rightarrow C(s)_{graphite}+O_2(g)\)

As, carbon dioxide and oxygen gases are present in the same phase and in opposite sides of the chemical reaction. So, it can be cancelled out.

Net reaction follows: \(C(s)_{diamond}\rightarrow C(s)_{graphite}\)

Hence, the correct answer is Option C.