Indicator Question (1 Viewer)

Talia95

New Member
Joined
Oct 28, 2013
Messages
24
Gender
Undisclosed
HSC
N/A
How did you explain why it would work as an indicator?
 
Joined
Apr 29, 2012
Messages
39
Gender
Male
HSC
2013
How did you explain why it would work as an indicator?
pH indicators need to accommodate proton transfers and provide a distinguishable colour change. I put down it would work primarily for weak acids as their equivalence point is somewhere in the 3-7 range. Any thoughts on this?
 

Frie

Wannabe Inventor
Joined
Nov 18, 2012
Messages
75
Gender
Male
HSC
2013
Isn't it HInd + H2O <-> Ind- + H3O+

In acid, equilibrium shift to left, so colour would be same as HInd (red i think?)
In acid, use up H3O+, shift to right, Ind- colour (green?)

Neutral in middle, forgot what red + green = tho.

Is this explanation ok?
 

superSAIyan2

Member
Joined
Apr 18, 2012
Messages
320
Gender
Male
HSC
2013
^ thats what i wrote. but didnt talk about neutral since you dont know where the equilibrium position lies normally.

You should mention that its an appropriate indicator since it gives two distinct colours in acidic and basic solutions, thus allowing us to identify them as acids or bases.
 

Locus

Member
Joined
Jul 30, 2013
Messages
77
Gender
Male
HSC
2013
^ thats what i wrote. but didnt talk about neutral since you dont know where the equilibrium position lies normally.

You should mention that its an appropriate indicator since it gives two distinct colours in acidic and basic solutions, thus allowing us to identify them as acids or bases.
sai did u get overestimation or udnerestimatiom
 

nifkeh

Member
Joined
May 29, 2012
Messages
385
Gender
Female
HSC
2013
^ thats what i wrote. but didnt talk about neutral since you dont know where the equilibrium position lies normally.

You should mention that its an appropriate indicator since it gives two distinct colours in acidic and basic solutions, thus allowing us to identify them as acids or bases.
I wrote this too because I was thinking of buffers
 

superSAIyan2

Member
Joined
Apr 18, 2012
Messages
320
Gender
Male
HSC
2013
sai did u get overestimation or udnerestimatiom
im quite sure that you overestimate HCl. the actual number of moles of sodium carbonate in the conical flask is less than what you calculate (since you incorrectly rinsed and filled the pipette). hence a lower volume of HCl will be used in the titration and you will get a higher concentration
 

Locus

Member
Joined
Jul 30, 2013
Messages
77
Gender
Male
HSC
2013
im quite sure that you overestimate HCl. the actual number of moles of sodium carbonate in the conical flask is less than what you calculate (since you incorrectly rinsed and filled the pipette). hence a lower volume of HCl will be used in the titration and you will get a higher concentration
Awesome ... changed it to overestimtion after reading it again
 

superSAIyan2

Member
Joined
Apr 18, 2012
Messages
320
Gender
Male
HSC
2013
lol i was stuck on that question so long cos i wasnt bothered to read the steps. I thought the picture of the pipette was the burette for a long time
 

vtx

Member
Joined
Mar 22, 2013
Messages
30
Gender
Male
HSC
N/A


Then you talk about Le Chatelier's principle and how colour of solution changes as concentration of hydronium and hydroxide change etc.
It can be used as an indicator since colour change is distinct.
 

Menomaths

Exaı̸̸̸̸̸̸̸̸lted Member
Joined
Jul 9, 2013
Messages
2,374
Gender
Male
HSC
2013
Aaaaaaaaaaaaaaaaaand I just wrote 'he will get a titration calculation error' because blah blah :(
 

superSAIyan2

Member
Joined
Apr 18, 2012
Messages
320
Gender
Male
HSC
2013


Then you talk about Le Chatelier's principle and how colour of solution changes as concentration of hydronium and hydroxide change etc.
It can be used as an indicator since colour change is distinct.
damn should have mentioned LCP. i just said, in acidic solution the Hydronium conc increases, so the equilibrium shifts left to decrease H30+ conc. this increases the concentration of HINd, giving a red colour. Similar thing for basic solutions
 

Queenroot

I complete the Squar3
Joined
Sep 11, 2011
Messages
7,473
Location
My bathtub
Gender
Female
HSC
N/A
Aaaaaaaaaaaaaaaaaand I just wrote 'he will get a titration calculation error' because blah blah :(
Oh yes that question, I wasn't sure how to improve the validity. I thought he should just start again...
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top