Acids and stirring

[gbroadbridge]

Is it necessary to stir an acid such as hydrochloric acid used for titration tests?

I've seen conflicting statements and I'm not sure.

Does it even matter?

 

[Dan_P]

Is it necessary to stir an acid such as hydrochloric acid used for titration tests?

I've seen conflicting statements and I'm not sure.

Does it even matter?

It definitely matters. If the drop of titrant is not mixed, the end point of the titration will be missed, i.e., too much acid will be added.

Only gentle mixing is needed after each drop is added. Just swirl the sample vessel briefly.

 

[gbroadbridge]

It definitely matters. If the drop of titrant is not mixed, the end point of the titration will be missed, i.e., too much acid will be added.

Only gentle mixing is needed after each drop is added. Just swirl the sample vessel briefly.

Apologies, my question was not clear

My question really is, does the acid sitting in the bottle need to be stirred before being used or does it not matter?
So I have a bottle of 0.1N acid, do I need to shake or stir that bottle before being used? For automatic titration testing to determine alkalinity, is it necessary to periodically stir the acid, or can it just sit in a bottle?

I understand that the titration itself requires stirring or swirling.

 

[gbroadbridge]

What? Really? No answers after 3 hours?

Must be more complicated than I first thought.

 

[Dan_P]

Apologies, my question was not clear

My question really is, does the acid sitting in the bottle need to be stirred before being used or does it not matter?
So I have a bottle of 0.1N acid, do I need to shake or stir that bottle before being used? For automatic titration testing to determine alkalinity, is it necessary to periodically stir the acid, or can it just sit in a bottle?

I understand that the titration itself requires stirring or swirling.

Solutions do not need to be stirred before using. If there is condensation near the top, you might consider turning the bottle over a couple times. That said, I can’t see that it will make a detectable difference if you don’t.

 

[Randy Holmes-Farley Verified Community Expert]

What? Really? No answers after 3 hours?

Must be more complicated than I first thought.

Most users are not on Sydney time. lol

As noted by Dan, any clear water solution, including acids, do not ever need stirring. They cannot ever settle or otherwise become inhomogeneous unless there are other phases present, such as a solid material or a second liquid phase (like oil and water).

In this case, acid solutions for titrations do not benefit from stirring.

 

[dwest]

Apologies, my question was not clear

My question really is, does the acid sitting in the bottle need to be stirred before being used or does it not matter?
So I have a bottle of 0.1N acid, do I need to shake or stir that bottle before being used? For automatic titration testing to determine alkalinity, is it necessary to periodically stir the acid, or can it just sit in a bottle?

I understand that the titration itself requires stirring or swirling.

No.

 

[gbroadbridge]

Most users are not on Sydney time. lol

As noted by Dan, any clear water solution, including acids, do not ever need stirring. They cannot ever settle or otherwise become inhomogeneous unless there are other phases present, such as a solid material or a second liquid phase (like oil and water).

In this case, acid solutions for titrations do not benefit from stirring.

Okay, this directly contradicts advice given by vendors of certain alkality testers which measure pH and the amount of an acid delivered in order to measure Alkalinity.

They state that the acid will settle into Hydrogen and Chloride Ions at the bottom of the bottle which I thought sounded like hokus pokus but I thought would run by real chemists.

Thanks for the clarification.

P.S. Yes I do realise the world does not revolve around Sydney, as much as we may wish.

 

[Randy Holmes-Farley Verified Community Expert]

They state that the acid will settle into Hydrogen and Chloride Ions at the bottom of the bottle which I thought sounded like hokus pokus but I thought would run by real chemists.

Well, I for sure would never, ever take advice from someone who claimed such an obviously incorrect statement. Seriously, that's over the top ignorance of chemistry.

 

[gbroadbridge]

Well, I for sure would never, ever take advice from someone who claimed such an obviously incorrect statement. Seriously, that's over the top ignorance of chemistry.

Reef factory customer support says you must stir their titration solution which is simply 0.02N HCl.

I'm in the midst of a discussion about this, but wanted to get an expert opinion before I called it total BS.

 

[Randy Holmes-Farley Verified Community Expert]

Reef factory customer support says you must stir their titration solution which is simply 0.02N HCl.

I'm in the midst of a discussion about this, but wanted to get an expert opinion before I called it total BS.

If there is nothing else in it, that's just wrong.

 

[gbroadbridge]

If there is nothing else in it, that's just wrong.

That's a good call.

I've been using a 0.02 HCl solution diluted down from a bulk supply of 0.1N from Hanna and it works just fine.

I suppose that if Reef factory have added a magic component I'd never know, but if I would never know it cannot be that important

I still think that magic Chloride and Hydrogen Ions settling to the bottom of a bottle needs to be challenged and I feel like a fight right now.

 

[Randy Holmes-Farley Verified Community Expert]

I still think that magic Chloride and Hydrogen Ions settling to the bottom of a bottle needs to be challenged and I feel like a fight right now.

There’s no question that if they use those words, they are wrong. Neither chloride nor hydrogen ions ever settle from a water solution. Brownian motion keeps them perfectly mixed under all conditions short of freezing with ice formation (they are excluded from ice).

 

[Malcontent]

There are people in the freshwater forums who think they'll get higher ammonia readings if they draw the sample from the bottom of the tank...

 

[gbroadbridge]

There’s no question that if they use those words, they are wrong. Neither chloride nor hydrogen ions ever settle from a water solution. Brownian motion keeps them perfectly mixed under all conditions short of freezing with ice formation (they are excluded from ice).

I'm quite looking forward to this argument

But that is a fight for tomorrow, as it's close to midight here and as Randy pointed out,
we are not all in the same timezone.

 

[taricha]

They state that the acid will settle into Hydrogen and Chloride Ions at the bottom of the bottle

LOL. Thanks for this. That's one of my new favorite vendor nonsense "explanations" that I've heard in a while. high comedy.