Answer : The number of moles of hydrogen gas is, 0.033 mole
Explanation : Given,
Moles of sodium = 0.066 mole
The balanced chemical reaction will be,

From the balanced chemical reaction, we conclude that 2 moles of sodium react with 2 moles of water to give 2 moles of sodium hydroxide and 1 mole of hydrogen has as a product.
As, 2 moles of sodium react to give 1 mole of hydrogen gas
So, 0.066 mole of sodium react to give
moles of hydrogen gas
Therefore, the number of moles of hydrogen gas is, 0.033 mole