It is C 2 1 2 1
You have to 1st balance the nitrates then balance the silvers to get the coefficients
Explanation:
32
2H
2
+O
2
→2H
2
O
Molecular mass of H
2
=2 g/mol
Molecular mass of O
2
=32 g/mol
From the balanced chemical equation,
2×2=4 g of hydrogen requires 32 g of Oxygen to react completely
It's not, if it were it would be ice. The water is a bit warmer.