[sladefungus]

I inherited my lovely plot 2 years ago and have just found a large unlabelled bag in the shed containing a very fine white/grey powder. 
How can i tell if this is lime?
If i add vinegar will it bubble and give off CO2?
its been a long time since my A level chemistry!

[solway cropper]

It might lime and you're right it will fizz if you put it in vinegar. On the other hand it might something like Cymag which we used to use to kill wasps nests and to chuck down rabbit holes. If you mix it with water it releases cyanide gas. If I found an unlabelled powder I'd be inclined to give it a wide berth and dispose of it carefully. All manner of nasty stuff was used on allotments in the olden days. To quote Clint Eastwood....do you feel lucky?

[sladefungus]

Ah, thanks for that!
There's an awful lot of it so unless the previous owner had a very big rabbit / wasp problem im inclined to think its not that.  I guess i could just compare it to the lime for sale in the allotment store....

[sunshineband]

Go careful there Sladefungus: visual comparison isn't necessarily accurate in Id of strange white powders stored for who knows how long

I'd get rid if it were me --   take it to the allotment shop maybe and ask where you could dispose of it 

[mumofstig]

I'd ask in the allotment shop if this is how they sell their lime. They may recognise it immediately

[JayG]

Add a small amount of white malt vinegar to a sample of your powder. If it fizzes it is a good indication that it is powdered chalk or limestone.

When it stops fizzing pour off some of the clear liquid. To this add the clear liquid made by dissolving bicarbonate of soda in boiling water (it will fizz) (note: not baking soda), or washing soda in cold water.

If the powder originally contained lime this will produce insoluble calcium carbonate which will turn the liquid milky, or even be visible as a white precipitate.

Just in case your material is something very unusual and nasty it might be advisable to do the experiment outdoors!

[Janeymiddlewife]

I'd just take it to your local refuse disposal site, when we were clearing my dad's shed out there were all sorts of strange powders/liquids in unlabelled containers - I just handed them to a member of staff, no fee, no questions asked - just don't turn up in a white van or they'll charge you trade fees!

[mumofstig]

bicarbonate of soda in boiling water (it will fizz) (note: not baking soda), or washing soda in cold water.

Bicarbonate is baking soda?

Wikipedia: Since it has long been known and is widely used, the salt has many related names such as baking soda, bread soda, cooking soda, bicarbonate of soda.

[zazen999]

bicarbonate of soda in boiling water (it will fizz) (note: not baking soda), or washing soda in cold water.

Bicarbonate is baking soda?

Wikipedia: Since it has long been known and is widely used, the salt has many related names such as baking soda, bread soda, cooking soda, bicarbonate of soda.

I think they must mean Baking Powder, which is Bicarb with cream of tartar added.

[Paul Plots]

If it doubt throw it out!

You could test with acid (vinegar) - it may bubble but....  :blink: If it is Co2 it should put out a lighted splint... it if isn't then the gas could help to trim your eye-brows!!

Your local refuse tip should have a special area for the disposal of unwanted chemicals and they will take care of this for you.

The price of a new bag of lime is not so high that it is worth taking a risk in MHO 

[beansticks]

Sounds like Cocaine to me

[DD.]

You definitely shouldn't mix that with acid!

[randombod]

GET RID safest way

[Paul Plots]

You definitely shouldn't mix that with acid!

Read all about it: "Local allotment launched into space"

Not funny      :blink: 

[JayG]

Read all about it: "Local allotment launched into space"

Not funny      :blink: 

At least your carrots would be high enough to escape carrot fly!

Apologies for a senior moment, I should have said "not baking powder" rather than "not baking soda".

The experiment is a very simple and safe one, and as a lifelong dabbler I would be unable to resist trying, but I have to agree that if you are in any doubt it is fairly easy to dispose of safely and the real thing is not expensive to buy.

Of course, if it really is cocaine...........................