Redox reaction

hey

In which reaction does Hydrogen behave as an oxidising agent?

   0      0          +1  -1

1)H2 + Cl2 --> 2HCl

   +2  -1    0          +3  -1

2)C2H4 + H2 -->  C2H6

   0       0            +3  -1

3)N2 + 3H2 --> 2NH3

    0        0           +1   -1

4)2Na + H2 --> 2NaH

 

In the second equation, oxidation number of H in H2 (0) decreases to -1 in C2H6, while oxidation number of C in C2H4 (+2) increases to +3 in C2H6. Isn't H an oxidising agent in this case? The answer given is the last equation, which is also correct. I'm confused. Isn't equation 2 valid too?

In equation 2, the oxidation number of hydrogen is +1, and that of carbon is -2 in C2H4, and -3 in C2H6. 

The reason for this is the electronegativity of C is 2.4 and that of H is 2.1. That is why equation 4 is the correct answer.