Check all that apply.

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)

-4 for C in CH4

+4 for C in CO2

-2 for O in all substances

+1 for H in both CH4 and H2O

+4 for O in H2O

4 for C in CH4

+4 for C in CO2

-2 for O in all substances

+1 for H in both CH4 and H2O

option 1,2,3 and 4 are correct. Option 5 is not correct

Explanation:

Step 1: Data given

Oxidation number of H = + 1

Oxidation number of O = - 2

Step 2: The balanced equation

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g)

Step 3: The oxidation numbers

-4 for C in CH4

⇒ Oxidation number of H = + 1

⇒ 4x + 1 = + 4

C has an oxidation number of - 4

This is correct.

+4 for C in CO2

⇒ Oxidation number of O = - 2

⇒ 2x - 2 = - 4

C has an oxidation number of + 4

This is correct.

-2 for O in all substances

⇒ this is correct, the oxidation number of O is always - 2 (except in H2O2 and Na2O2)

This is correct.

+1 for H in both CH4 and H2O

⇒ this is correct, the oxidation number of H is always + 1 (except in metal hydrides).

This is correct.

+4 for O in H2O

⇒ Oxidation number of H = + 1

⇒ 2x + 1 = + 2

The oxidation number of O is - 2

This is not correct