The half equivalence point occurs where half the volume of NaOH is added to get to equivalence. So if equivalence took 20 ml, then half equivalence is 10 ml.
Original post by EierVonSatan
The half equivalence point occurs where half the volume of NaOH is added to get to equivalence. So if equivalence took 20 ml, then half equivalence is 10 ml.
The thing was, i was given data to plot, so
0.00 naoh had ph 5.1
1.00 naoh had ph 7.9
This was the biggest jump, so would the volume needed for half neutralisation be like 0.5cm^3. Is the rest of the curve there to trick me? after the ph is above 7 does this mean there is no acid left?
Just a more nice curve for a pKa 6.5 acid titrated with sodium hydroxide:
100% is the equivalence point (as defined by the stoichiometry).
100% is the equivalence point (as defined by the stoichiometry).
Original post by Borek
Just a more nice curve for a pKa 6.5 acid titrated with sodium hydroxide:
100% is the equivalence point (as defined by the stoichiometry).
100% is the equivalence point (as defined by the stoichiometry).
At 0.00 NaOH the ph was 5.1, it then shot up to 7.9 when 1.00 NaOh was added. is the half equivalence between these two points or have i done it all wrong?
Original post by Borek
How much NaOH was added to reach the end point?
That what I'm confused about, I though that the end point is between when the solution is acidic and basic i.e. between the jump from 5 to 8.
Original post by Mo_maths
That what I'm confused about, I though that the end point is between when the solution is acidic and basic i.e. between the jump from 5 to 8.
It's more likely that your end point is the part between 8 and 11 pH, where the graph is steepest. What does 28 refer to on your graph? Is it 28 ml?
Since both solutions are equal concentration, you would expect an equal volume of NaOH is needed to reach the equivalence point for the volume of weak acid (assuming it is monoprotic). So 1 ml isn't realistic if the volume you are titrating against is roughly 20-30 ml.
Original post by EierVonSatan
It's more likely that your end point is the part between 8 and 11 pH, where the graph is steepest. What does 28 refer to on your graph? Is it 28 ml?
Since both solutions are equal concentration, you would expect an equal volume of NaOH is needed to reach the equivalence point for the volume of weak acid (assuming it is monoprotic). So 1 ml isn't realistic if the volume you are titrating against is roughly 20-30 ml.
Since both solutions are equal concentration, you would expect an equal volume of NaOH is needed to reach the equivalence point for the volume of weak acid (assuming it is monoprotic). So 1 ml isn't realistic if the volume you are titrating against is roughly 20-30 ml.
Yeah I had a feeling id done it wrong, but that was only one mark ( finding volume of end point) would you say a pka of 6.5 sounds ok?
Original post by Mo_maths
That what I'm confused about, I though that the end point is between when the solution is acidic and basic i.e. between the jump from 5 to 8.
No, if the titrated acid is weak end point is at pH higher that that. For acid with pKa 6.5 pH of the endpoint is around 9.6 (as marked on the titration curve I posted).
Original post by Borek
No, if the titrated acid is weak end point is at pH higher that that. For acid with pKa 6.5 pH of the endpoint is around 9.6 (as marked on the titration curve I posted).
Sorry I meant for half equivalence, the question was draw the graph and find half equivalence to work out ka.. or is that still wrong :/ we had to find pka from the graph
Quick Reply
Related discussions
- A level chemistry
- Btec applied science unit 2
- Titration questions
- OCR Chemistry Paper 1 GCSE 2022 (triple higher)
- Etha
- gcse chemistry help
- Titration paper
- hard titration alevel chem Q!
- Chemistry Calculation Question
- Indicator colour question.
- Kc Titration Question
- Titration and Moles question
- Redox reaction and titration
- As level / a level chemistry concentration help!!
- AQA A Level Chemistry REDOX titration q
- Chem alevel help
- A Level Chemistry HELP
- gcse chemistry help - making fertilisers
- AS Titrations?
- [URGENT] stuck on titration a level chemistry question
Latest
Trending
Last reply 6 days ago
Im confused about this chemistry question, why does it form these productsTrending
Last reply 6 days ago
Im confused about this chemistry question, why does it form these products
