the pale pink color of titration solution fade to colorless after several minutes?

Question

When NAOH exposed to the atmosphere, the pale pink color of the titration fad to colorless. Can someone account for this color change?

Answer 1

The pink is an indication of slightly basic. However, the CO2 in the air will dissolve in water and form carbonic acid. The acid will neutralize the OH-, and the color fades.

Answer 2

Pale Pink Color

Answer 3

Depends on which indicator you're employing. Some indicators are oxidized by oxygen gas, for instance dianisidine (3,3 methoxybenzidine). The reduced form is colorless, however, exposure to open air of the solution turns the solution with the indicator to a pinkish color; the same for the solid matter form of the indicator reagent. Thus the situation is the reverse from what you've observed, however, you need to account for the particular indicator used and also it seems that you haven't described the context of the experiment adequately for a proper and accurate analysis of your observation.

Answer 4

More likely you are titrating some multi-protic acid with sodium hydroxide, using phenophthalein as an indicator.

If you titrate too quickly, you will get a pink color that will slowly fade as the acid releases more hydronium ions to solution from a second ionization.

Answer 5

So the solution started out basic, and the indicator faded away with time, indicating that the solution was becoming more acidic? If so then , it would be because of dissolved gases changing the pH. A common example is sulfates and nitrates dissolved in rain to produce... acid rain. I don't remember the exact equations but I am sure someone else will point them out.

Answer 6

naw he's wrong. it turns a bright pink when its completely neutralized. what ure talking about happens when its not quite finished. if you keep titrating itll start 2 turn pink because some of it is being neutralized after a while itll take longer and longer to go back colorless. once it is fully neutralized itll b bright pink. the darker the pink the farther uve gone pass.

Answer 7

well, i'm not sure, but i think it is completely neutralized, i could be wrong again. the H+ ions go into the air, just like ammonia would do. i'm doing the lab tomorrow, so i'll tell you about it, but won't be able to, maybe i can add onto it. or maybe i won't give a damn really and forget i was ever writing to you.

Answer 8

That's not right

Answer 9

Well, it depends..