Yeah it's in unit 3
Basically, to do a titration reaction you should write out both compounds first with their formula then write the labels 'moles, volume, concentration) under BOTH.
Na
2S
2O
3 (Sodium Thiosulphate) moles - volume - concentration -HCl (Hydrochloric acid)moles - volume -concentration - Now, as we can see there is no integer (the whole number before the formula, there is a proper name for this but I've totally forgotten it atm lmfao) it means the ratio of the two compounds is 1:1, if one of them had a 2 infront it would be 2:1, if one had a 2 infront and one had a 3 infront it would be 2:3 and so on. Usually at GCSE they will only make the compound 1:1 as you don't get the formula for this so it's alot to remember.
Okay, so now you fill in the 'volume, concentration' with all the information you've been given in the question. Whichever you have the information of both the volume and concentration for, is the one we will work with.
Something you MUST remember is that you can only write the concentation in dm3. Like in your question, they do sometimes give it in cm3 and if you wrote that you'd lose marks basically. To get to dm3 from cm3 you do cm3 / 1000.
(I have divided them both by 1000 and wrote them as dm3 below)
ratio 1:1
Na
2S
2O
3 (Sodium Thiosulphate) moles - volume - 0.05dm3concentration -HCl (Hydrochloric acid)moles -volume - 0.005dm3concentration -Now I've got to this point and realised you didn't say a concentration for any lmfao! Do you have a concentration for either or am I working with the 70% concentration I suggested?