Question

Sodium oxide, reacts with water to give NaOH. A) Write a balance equation? B)What is the pH of the solution prepared by allowing 1.55 g of Na2O to react with 500.0 ml of water? (assume there is no volume change) C) How many milliliters of 0.0100M HCL are needed to neutralize the NaOH prepared in(b)

Answer 1

A.
Na2O + HOH ==> 2NaOH

B. There is a long way and a short way of doing this. The long way is to make a stoichiometry problem out of it, convert g Na2O to moles, calculate moles NaOH formed, then use M = moles/L.
A shorter way is to forget about stoichiometry and reason it out.
moles Na2O = 1.55 g/molar mass Na2O = ??
moles NaOH = 2*moles Na2O
M = moles/L
M NaOH = molarity of OH^-
Then pOH = -log(OH^-) and
pH + pOH = pKw = 14
Solve for pH.

C. Use
mL acid x M acid = mL base x M base.
Solve for the unknown, mL acid.

Answer 2

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