Question

hydrogen energy is energy that comes from hydrogens. we harness hydrogen energy through hydrogen fuel cells.
the image below is a simplified illustration of how energy from hydrogen is produced. the only byproduct is water!
hydrogen fuel cell
water out
hydrogen in
oxygen in
energy out
choose the correct answer.
when hydrogen combines with oxygen, energy is released. what substance forms during this process?
water
salt
nitrogen

Explanation:

The reaction between hydrogen ($H_2$) and oxygen ($O_2$) is $2H_2 + O_2
ightarrow 2H_2O$. The product of hydrogen and oxygen combining is water. The diagram also shows "water out" from the hydrogen fuel cell, confirming this. Salt (like NaCl) forms from reactions involving metals and acids or bases, and nitrogen is unrelated here.

Answer:

A. Water