Argon (Ar) is an element in group 18. Argon is . a gas highly reactive
a metalloid
a good conductor of heat

Stoichiometric coefficients are th' moles of reactants needed or th' moles of products formed in the reaction.

According to th' question :-

The balanced chemical equation for this synthesis reaction looks like this :-

2 H₂ + 2 O₂ —-—→ 2 H₂ O

∵ Th' reaction requires 2 moles of hydrogen gas and 1 mole of oxygen gas to produce 2 moles of water.

4.6 mol. O2 × 4 mol. of H2O × 18 g H2O

Divide th' above from :-

5 mol. O2 × 1 mol. H2O

The answer after calculations = 66 g

Hence,

66 g of water will be produced from 4. 6 moles of Oxygen.