Chemistry Solution Stoichiometry

Question

If 4.0 g of sodium metal completely reacts with 38.1 mL of pure water (which is in excess), what is resulting molarity of the sodium hydroxide solution?

Answer 1

1. 2Na + 2H2O - 2NaOH + H₂

_{4 grams of Na is 0.174 moles ( to find the moles divide grams by the atomic mass of Na which 23 grams)}

As per the above equation the ratio of Na and NaOH are 2:2 that is 1:1 that means 0.174 moles of NaOH is formed. Divide the moles of NaOH by the volume in liters( 38.1 mL is 0.0381 liters)

The molarity of NaOH 0.174 moles/.0381= 4.57 moles/ liter