N h2o = mh20/Mh20
= 8.0g/18g/mol
=0.44 mol
therefore n O = 0.44mol
therefore n H2 = 0.88 mol
m H2 = n H2 * M H2
= 0.88 mol * 2 g/mol
=1.76 g
Answer: A - Carbon
Explanation: Hope this helps!
Your answer is boron,
I looked at the periodic table, there is nothing else that falls under this specs.