This is for a titration, to measure the amount of acid that can be neutralised by gaviscon. I know how to work out the first 3 but I'm not sure on the others.

Question

I think i need to use the calculation c=n x v but i don't know where and why?
Theory. How do you work them out?

(i)Calculate the amount (in moles) of sodium hydroxide used in the titration
(ii)Write the balanced equation for the reaction between sodium hydroxide and hydrochloric acid
(iii)State the amount (in moles) of hydrochloric acid present in the 20cm³ sample used in the titration
(iv)Calculate the amount (in moles) of hydrochloric acid remaining in the solution made with the gaviscon tablet
(v)Calculate the amount (in moles) initially used to react with the tablet
(vi)Calculate the amount (in moles) of hydrochloric acid that reacted with the tablet
(vii)Assuming that the tablet contains an insoluble metal hydroxide, calculate the amount (in moles) of hydroxide ions present in each tablet

Answer 1

i)Calculate the amount (in moles) of sodium hydroxide used in the titration
mols NaOH = M x L

(ii)Write the balanced equation for the reaction between sodium hydroxide and hydrochloric acid
NaOH + HCl ==> NaCl + H2O

(iii)State the amount (in moles) of hydrochloric acid present in the 20cm³ sample used in the titration
<mols HCl = M x 0.020 L.
There isn't enough information given to calcualte the others. It appears that you added HCl (an excess) to the commercial tablet and back titrated with NaOH
(iv)Calculate the amount (in moles) of hydrochloric acid remaining in the solution made with the gaviscon tablet
(v)Calculate the amount (in moles) initially used to react with the tablet
(vi)Calculate the amount (in moles) of hydrochloric acid that reacted with the tablet
(vii)Assuming that the tablet contains an insoluble metal hydroxide, calculate the amount (in moles) of hydroxide ions present in each tablet