apiguard in November?

[Vergilius]

Don't do an apiguard treatment now; weather set to cool down considerably over the next week or so. If necessary, do a mid-winter oxalic treatment instead.


Ben P

 

[boca]

10% is a little high as well.

Oxalic acid solubility in water 90 g/dm3 (at 20 °C)

Have they used high temperature solution?

 

[oliver90owner]

Does it matter? The quoted value is an equilibrium value at the temperature quoted.

Dissolving the solid iinitially with a solvent/solution temperature warmer than twenty degrees, initially, may well attain an equilibrium value much more quickly for 20 degrees Celsius.

RAB

 

[boca]

In the equilibrium state we have 9% (w/v) solution not 10%

 

[oliver90owner]

Err, yes. 90 per 1000 is 9 per100 is 9%. Do we have a problem anywhere with this?

It does not affect oxalic acid trickling, surely, at around the 3% concentration? Not sure of the gradient of the solubility v temperature and so the temperature required for a 10% w/v, but I would not expect it would be a large increase over twenty degrees.

Of course when making up these solutions with the dihydrate form, the amounts weighed/measured will be much different than the actual concentration of oxalic acid calculated as the anhydride. That seems to cause a certain amount of confusion amonst some on the forum.

RAB

 

[For want of a better word]

Try making a molar solution of NaOH..................
has to be DRY !