Question

why curd should not be stored in copper vessel

Answer 1

Hey.... Hope tht it will help u.
Curd is made up of milk which is slightly acidic in nature as we know it contains lactic acid so, we can can say that curd is acidic in nature (or by basic definition of acids i.e acids are sour in taste)

Acids reacts with metal to give H2 and respective salts

hence, when curd is placed in copper container it reacts with Cu to form Poisonous compounds which may be unfit for human consumption.

Curd(acidic substance) + Cu gives metallic salts(unfit for consumption).