Question

question 3 (2 points)
the element that is oxidized in this reaction is ________.
ch₄ (g) + 2 o₂ (g) → co₂ (g) + 2 h₂o (g)
h
c
o
none of these since this is not a redox reaction

Explanation:

Step1: Determine oxidation numbers of C in reactant

In $CH_4$, hydrogen has an oxidation number of +1. Let the oxidation number of C be $x$. Using the rule that the sum of oxidation numbers in a neutral compound is 0, we have $x+(+1)\times4 = 0$, so $x=- 4$.

Step2: Determine oxidation numbers of C in product

In $CO_2$, oxygen has an oxidation number of -2. Let the oxidation number of C be $y$. Using the rule that the sum of oxidation numbers in a neutral compound is 0, we have $y+(-2)\times2=0$, so $y = +4$.

Step3: Identify the oxidized element

Since the oxidation number of carbon increases from -4 in $CH_4$ to +4 in $CO_2$, carbon is oxidized.

Answer:

B. C