Acid/base

[Mao]

Just abit in conflict here.

Been thinking about it all day, and soz for bugging you about this. But,

With titration 3 - 11

Isn't the 3 still beneath 3.1

and the 11 above 10.0


and the 2 and 12, is similar?

So where do you draw the line on why it isn't suitable. ):

No, the equivalence point is at 7. We need the indicator to change at the sharp transition. If the entire range is from 3 to 11, then the sharp transition period would be around say 5 to 9. Then the indicator choice becomes important.

[Water]

Say if it was a solution of 0.001M HCl vs 0.001M NaOH, then the starting pH would be 3, the equivalence point is 7, and then a limiting behaviour of pH=11 as more NaOH is added. Would you then suggest we use methyl orange 3.1- 4.4 or phenolphthalein 8.3 - 10.0 given that our titration is between 3 and 11?





Mao, why not use Phenolphalein, in this case. When its diluted solution.


We'd have a Basic Pink Colour, to an Acidic Coluorless. Wouldn't this be a good indicator? As the color would be distinctly different, even if its diluted.