<h3>Answer:</h3>
17.25 g of Na
<h3>Explanation:</h3>
The balance chemical equation is as follow,
2 Na + 2 H₂O → 2 NaOH + H₂
As we know that one mole of any Ideal gas at standard temperature and pressure occupies exactly 22.4 dm³ (1 L) volume.
Then, according to equation,
22.4 L (1 mol) H₂ was produced by = 46 g (2 mol) of Na
Then,
8.40 L H₂ gas will be produced by = X g of Na
Solving for X,
X = (8.40 L × 46 g) ÷ 22.4 L
X = 17.25 g of Na
