Question

Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is .... x 10^-1 M. (Nearest integer)

[Atomic mass : Na = 23.0, O = 16.0, H = 1.0]

Answer 1

Answer is 13

Na₂O + H₂O → 2NaOH

\(\frac{20}{62}\) moles

Moles of NaOH formed = \(\frac{20}{62}\times2\)

[NaOH] = \(\frac{40}{\frac{62}{\frac{500}{1000}}}\) =1.29 M = 13 x 10^-1

(Nearest integer)