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What is a titration? (2 Viewers)
- Thread starter leesh95
- Start date
deswa1
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- Joined
- Jul 12, 2011
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- Male
- HSC
- 2012
Lol I already did that before coming here but I'm having a hard time comprehending the concept. Hence why I posted here.
deswa1
Well-Known Member
- Joined
- Jul 12, 2011
- Messages
- 2,256
- Gender
- Male
- HSC
- 2012
Oh ok. In that case I'll explain it.
Basically with a titration, you are trying to find the concentration of an unknown liquid. So lets say if we want to find the concentration of 25mL of a sodium hydroxide solution. Now we need to react it with something where we know the EXACT concentration. So lets say we have a bottle that has a HCl solution of EXACTLY (or very, very close to) 1 mol/L. We can then react the two which will neutralise according to the following equation:
HCl + NaOH -> H2O + NaCl.
Now let's say it takes us 24 mL of HCl to complete the reaction (this is indicated by placing an indicator in the solution that'll change colour at the appropriate pH -> in this case you could use something like phenolpthalein because it will transition from colourless to pink in the range of the vertical titration curve).
So we just do simple molar calculations -> we know that one mole of HCl has to react with one mole of NaOH (from the equation). And we have n=cV=0.024(1) moles of HCl so we had this many moles of NaOH originally. Now use c=n/V because we know the volume of the sodium hydroxide and BOOM, you're done.
Did that make sense?
Basically with a titration, you are trying to find the concentration of an unknown liquid. So lets say if we want to find the concentration of 25mL of a sodium hydroxide solution. Now we need to react it with something where we know the EXACT concentration. So lets say we have a bottle that has a HCl solution of EXACTLY (or very, very close to) 1 mol/L. We can then react the two which will neutralise according to the following equation:
HCl + NaOH -> H2O + NaCl.
Now let's say it takes us 24 mL of HCl to complete the reaction (this is indicated by placing an indicator in the solution that'll change colour at the appropriate pH -> in this case you could use something like phenolpthalein because it will transition from colourless to pink in the range of the vertical titration curve).
So we just do simple molar calculations -> we know that one mole of HCl has to react with one mole of NaOH (from the equation). And we have n=cV=0.024(1) moles of HCl so we had this many moles of NaOH originally. Now use c=n/V because we know the volume of the sodium hydroxide and BOOM, you're done.
Did that make sense?