what is the volume of sulfuric acid in a 400 ml water of 0.05 mol/L solution

Question

I want to prepare a solution on 400ml of 0.05 mol/L of standardized sulfuric acid, how much volume of sulfuric acid is required for preparation of standardized H2SO4 (0.05 mol/L). I have the concentrated H2SO4 (98% (w/w) and 1.84 as specific gravity) and i need to prepare 400mL of 0.05M from the concentrated solution.

Please provide steps (volume of concentrated acid needed and the volume it has to be diluted to)

Answer 1

98% w/w means 98 g H2SO4 per 100 g of solution

molar mass H2SO4 = 98 g / mole

Thus, 98 g / 100 g solution = 1 mol H2SO4 / 100 g solution.

Find moles H2SO4 needed to prepare 400 ml of 0.05 mol/L...

400 ml x 1 L/1000 ml x 0.05 mol/L = 0.02 moles H2SO4 needed to make 400 ml of 0.05 M

Find g of solution needed to provide 0.02 mol H2SO4...

1 mol H2SO4 / 0.02 mol H2SO4 = 100 g soln / x g soln and x = 2 g solution needed

Finally, convert g solution to mls solution using specific gravity...

2 g soln x 1 ml / 1.84 g = 1.09 mls of concentrated H2SO4

Since the value of 0.05 mol/L has only 1 significant figure, we should use 1 ml as our answer.

So, you would take 1 ml 98% H2SO4 and dilute it to a final volume of 400 mls.