[Palladipeloarancione]

From a wall drop outside rain water.

There's a soft white product in this point.

I think is calcium carbonate.

How can I test my hypothesis at home with simple reagents (vinegar, bleach ...)

Thanks,
Andrea

[Hunter2]

Vinegar is a good idea. Add some to the white material, if it gives some bubbles it is probably Carbonate. To be sure the obtained gas has to be conducted in a solution of Calcium hydroxide. Here it will give a white precipitation, which disappear after some time gas treatment.

It can be also Calcium nitrate, if the material is found in Toilet rooms, stables, farms, etc.

Calcium I think you cannot detected easily at home. need some test stripes or an complexometric titration.