Question

Which of the following equations is balanced?

Answer 1

The answer is B, because if you look, once you add the double hydrogen, that's when you balance out the equation. Hope this helps!  

Answer 2

Answer:

$2H_2 + O_2 --> 2H_2O$

Explanation:

If the equation is balanced then it means the number of atoms on the product side is same as the number of atoms on the reactant side.

So here as we can see that the reaction which will have same number of atoms on both sides is given as

$2H_2 + O_2 --> 2H_2O$

here on reactant side we can see 4 hydrogen atoms are given and 2 Oxygen atoms are present.

So if reaction is balanced then we can see that the number of atoms on product side is also 4 hydrogen atoms and 2 oxygen atoms.

So above reaction is balanced reaction