2.932 moles
Assuming the equation for the reaction in question is;
SnO₂(s) + 2H₂(g) → Sn(s) + 2H₂O(l)
Then we can answer the question given;
We are given;
We need to calculate the number of moles of H₂O produced;
To calculate the number of moles we divide mass of of a compound by its molar mass.
Molar mass of SnO₂ = 150.71 g/mol
Therefore;
Number of moles =221 g ÷ 150.71 g/mol
= 1.466 moles
From the equation, 1 mole of SnO₂ reacts to produce 2 moles of H₂O
Thus, the mole ratio of SnO₂ : H₂O is 1 : 2
Hence; Moles of H₂O = Moles of SnO₂ × 2
= 1.466 moles × 2
= 2.932 moles
Therefore, 2.932 moles of H₂O are produced.