Hi, this is a question on one of my lab reports and was just wondering if i get could get some insight into how i would work this out please.
Background: Synthesized a solid acid, diluted 3.00g of solid acid up to 100ml with distilled water.. titrated with 0.1M NaOH in 30ml aliquots.
Titre average = 11.2ml
Formula in title = H4SiW12O40
Question:
Assuming the formula given in the title, calculate the moles of titratable acidic protons per mole of compound. Compare this to your experimental results, show the maths for both and comment on the differences.
My attempt:
So to calculate the moles of titratable acidic protons per mole of compound i did,
grams used in titration/Mr of solid acid
3.00g/2976.297 = 0.001mol
Then multiplied that by 4? as there are 4 hydrogens in the molecular formula.
0.001 x 4 = 0.004mol of titratable acidic protons.
Then for my experimental results i have assumed that there is a 1:1 ratio between NaOH and the solid acid. So i worked out the moles in 100ml by using the titration value.
concentration x titre volume/1000 =
0.1 x (11.2/1000) = 0.00112mol
mol divided by aliquot multiplied by total volume
(0.00112/(30/1000)) x (100/1000) = 0.00373mol
then would i not need to multiply that number by 4? That value is close to the 0.004 i calculated in the first step but i cant help feeling im way off the mark.
Can anyone shed some light on this please?
Thanks in advance.