Help with hard titration

How would i solve this problem?

the answer is n=2
but whats the method behind it?



Thanks

You're correct until you get the amount of acid.

Next, using the 18.3cm3 volume to figure out concentration. You'll get 0.0679 mol dm-3 of acid.

Then you need the moles in the 250cm3 sample. You should get 0.0616 mol.

You need Mm. So you do mass/moles. You should get 117.76.

Then you use that to figure out n.
117.76-((12+16+16+1)*2)= 27.76

27.76/(12+2)=1.98
Round it up to 2
n=2

Sorry, i dont follow your line of working, could you break it down a little.to the
like what did you do the concentration of 0.0679 to get 0,616?

Learn these relationships, they're really important in calculations. I like to write them out at the top of the page as I find it really helpful!

Thank youuuuu so much, you dont realise how much i've been struggling doing these kinds of calculations

To get concentration I used the equation concentration=moles/volume.
Convert 18.4cm3 into dm3. 18.4/1000= 0.0184dm3.
Then I did (0.0025/0.0184)= 0.0679 mol dm-3.


Then you need amount of acid so you convert volume to dm3 again. 250/1000=0.25

Moles=Concentration*Volume
0.0069*0.25=0.016 mol