Question

Why should curd and sour substances not be kept brass and copper vessels?

Answer 1

So they are not kept in metal containers. Curd and sour substancescontain acid.They would react with the surface of metal vessels such as that of brass and copper to produce harmful substances. curd and sourthings have acid in them. ... So it is advised not to keep sour foo in copperor brass vessels.

Answer 2

curd has lactic acid

sour substance such as lemons have citric acid.

we know acids reacts with active metals to give salt and hydrogen

therefore when curd and and sour substance are kept in bass and copper vessels they react with the elements forming respective salt and hydrogen . so we should not keep them in brass and copper vessels.

Hope it is helpful...