Methanoic Acid vs Ethanoic Acid

[paulsutton]

Hi

I have been looking at a resource, on the Royal Society of Chemistry website.  This is a school investigation, to look at if toothpaste is basic, and therefore can neutralise an acid

https://edu.rsc.org/ideas/everyday-neutralisation-myths-busted/4015026.article

This investigation is aimed at UK Secondary aged students 11- 14 years.  I was thinking, if this could be adapted for use in primary schools ?  

This experiment uses  0.1 M ethanoic acid (danger: corrosive and flammable)   would using white vinegar (this is still ethanoic Acid ) be a good substitute for use in primary education.  ? Which is probably far safer.  I would guess vinegar is a much lower concentration or more diluted.

I am not a expert at all this,  but it should work.

Thanks

 

Paul Sutton

 

 

Edited February 3, 2022 by paulsutton

[studiot]

14 minutes ago, paulsutton said:

Hi

I have been looking at a resource, on the Royal Society of Chemistry website.  This is a school investigation, to look at if toothpaste is basic, and therefore can neutralise an acid

https://edu.rsc.org/ideas/everyday-neutralisation-myths-busted/4015026.article

This investigation is aimed at UK Secondary aged students 11- 14 years.  I was thinking, if this could be adapted for use in primary schools ?  

This experiment uses  0.1 M ethanoic acid (danger: corrosive and flammable)   would using white vinegar (ethanoic Acid) be a good substitute for use in primary education.  ? Which is probably far safer.

I am not a expert at all this,  but it should work.

Thanks

 

Paul Sutton

 

 

Lot's of queries here.

1) Where does the Methanoic acid, as trailed in your title come into it ?

2) 0.1M ethanoic acid contains 6 grammes per litre of acid. To be sold as vinegar the concentration must be at least 40g per litre.
So 0.1M is very dilute.

3) Very strong ethanoic acid (glacial acetic acid) is certainly corrosive and unsafe. I have not heard of it being particularly flammable of itself.

4) There are brands of toothpaste based on sodium bicarbonate (baking soda) which would be alkaline to a suitable strength of vinegar.

 

 

Edited February 3, 2022 by studiot

[paulsutton]

2 hours ago, studiot said:

Lot's of queries here.

1) Where does the Methanoic acid, as trailed in your title come into it ?

sorry, I mis read the list of items needed 0.1 M ethanoic acid ( there is a space in there for a reason eh) my bad but lack of experience with this.   Once i spotted this, I edited my original post but not the title. 

2 hours ago, studiot said:

2) 0.1M ethanoic acid contains 6 grammes per litre of acid. To be sold as vinegar the concentration must be at least 40g per litre.
So 0.1M is very dilute.

Ok thanks,   

3) Very strong ethanoic acid (glacial acetic acid) is certainly corrosive and unsafe. I have not heard of it being particularly flammable of itself.

Hmm, i was just quoting their information sheet,  i didn't think of it as flammable either.   This is why we have materials safety data sheets I guess to get accurate information.   If reaction with bicarbonate of soda would give of CO_2 anyway.

2 hours ago, studiot said:

4) There are brands of toothpaste based on sodium bicarbonate (baking soda) which would be alkaline to a suitable strength of vinegar.

The method uses 3 different brands,  one of which has bicarbonate of soda.   I have attached the method sheet for reference.

2 hours ago, studiot said:

Lesson to me here is make sure you read things properly,   one of the reasons I would get help to plan such an activity properly as in from the teachers, a 2nd pair of eyes (like here) would spot the error.

 

istoothpastebasicstudentsheet_513804.pdf

[studiot]

1 hour ago, paulsutton said:

sorry, I mis read the list of items needed 0.1 M ethanoic acid ( there is a space in there for a reason eh) my bad but lack of experience with this.   Once i spotted this, I edited my original post but not the title. 

Looks an easy mistake to make. Thanks for explaining that.

As to the flammability, the strongest (most concentrated) form of the acid is called glacial acetic acid, which is pretty reactive and some of these reactions can generate a lot of heat.

I looked up its flammability and sure enough its vapour can form explosive mixtures with air above 39^o C

ICSC 0363 - ACETIC ACID (inchem.org)

 

But you should never introduce glacial acetic acid at a primary school, and only with care at more advanced establishments.

Glacial acid is about 17.4M so 0.1M will be quite safe.

 

A couple of other thoughts.

Sodium bicarbonate can act as either a base or an acid, depending upon what it is reacting with.

Sodium or calcium carbonate is always basic. Chalk or limestone fizzes nicely and safely with various acids.

You should be careful not to confuse strength and concentration and certainly not say anything to introduce such a confusion to primary pupils.

 

I can remember half truths that were all to difficult to unlearn later from my school days.

 

 

 

Edited February 3, 2022 by studiot