Question

a 500ml stock solution of NAOH has a purity of 70% and a density of 1.9g/ml.
calculate the concentration that would be in a 1L solution.
calculate the molarity.
What volume would we have to take to prepare 250ml of a solution of 0.1 mol/l

Answer 1

The problem isn't worded very well. Calculate the concn IN WHAT UNITS. BELOW IS THE COnCN IN M = mols/L

For part b
M NaOH in 1 L is:
1000 mL x 1.19 g/mL x 0.70 x 1/molar mass NaOH = ? approx 33 M

Then use the dilution formula for part C.
mL1 x M1 = mL2 x M2
250 x 0.1 = mL2 x approx 33.