Answer:
The correct answer is product.
Explanation:
Hydrogen gas reacts with oxygen gas to generate water molecule.
2H2+O2 = 2H2O
We all know that that substances which are present at the left hand side of the equilibrium sign act as substrate and the substances those are present in the right hand side of the equilibrium sign are called products.
From that point of view it can be stated that water or H2O is the product of the reaction between hydrogen and oxygen.