Consider the redox reaction below.

Upper Z n (s) plus 2 upper H upper C l (a q) right arrow upper Z n upper C l subscript 2 (a q) plus upper H subscript 2 (g 0).

Which half reaction correctly describes the oxidation that is taking place?

Explanation:

Hello,

In this case, the described chemical reaction is:

Then, to identify the half reactions we must assign the oxidation state for each element as shown below:

In such a way, we can notice zinc's oxidation state changes from 0 to +2, therefore, it is the oxidizes species for which the half reaction which correctly describes the oxidation that is taking place is:

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c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.