Neutralisation.

Good afternoon All,
Like Lynn T I too have a brain drain.
I want to know how much 1M sodium hydroxide I need to add to a 100ml of 0.1M sodium hydroxide.
It took 17.5ml of 0.1M hydrochloric acid to neutralise 20ml of 0.1M sodium hydroxide.
I can't believe that I can't work this out!
 
Good afternoon All,
Like Lynn T I too have a brain drain.
I want to know how much 1M sodium hydroxide I need to add to a 100ml of 0.1M sodium hydroxide.
It took 17.5ml of 0.1M hydrochloric acid to neutralise 20ml of 0.1M sodium hydroxide.
I can't believe that I can't work this out!
I'm not completely sure what you are asking, but there appear to be two things here:
1) If you want to make 100ml of 0.1M Sodium Hydroxide from 1.0M then it is a dilution of 1/10th, so 10ml of NaOH and make up to 100ml with distilled water
2) However, HCl and NaOH react on a 1:1 ratio, so if it took 17.5ml of 0.1M Hydrochloric Acid to neutralise 20ml 0.1M Sodium Hydroxide then one of those concentrations is wrong - it could be the acid or the hydroxide, so I would advise making new solutions from scratch to be sure.
 
Thanks James, I have made up from fresh.
Can't I just add some 1M Sodium Hydroxide to the 0.1M Sodium hydroxide solution to make it equal strength to the 0.1M hydrochloric acid.
I make it 1.25ml of 1M sodium hydroxide to 100ml 0.1M Sodium hydroxide or dilute the hydrochloric acid?
 
Thanks James, I have made up from fresh.
Can't I just add some 1M Sodium Hydroxide to the 0.1M Sodium hydroxide solution to make it equal strength to the 0.1M hydrochloric acid.
I make it 1.25ml of 1M sodium hydroxide to 100ml 0.1M Sodium hydroxide or dilute the hydrochloric acid?
In theory yes, if you were sure that the acid was exactly 0.1M so that it was definitely the hydroxide that was wrong (if 17.5ml 0.1M neutralises it then it would suggest the NaOH is 0.0875M) then you could add more 1M to the solution to bring it up to the right concentration.

The problem is then how accurately you can dispense small volumes like 1.25ml. Basically unless it is a chemical that you have very little of, or is very expensive, then it is simpler to just start again.

Just to add that it isn't quite as simple as adding 1.25ml either, because that would give you the right amount of moles, but the volume would now be 101.25ml instead of 100ml, so the concentration would still be slightly out! Likewise if you removed 1.25ml and replaced it then you would then be slightly under. Far too much faff!
 
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:eek: Thank you James.
It's only for a simple making salt experiment.
Equal amounts of each , but the indicator paper needs to show neutral before they proceed.
 
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