1. Why should curd and sour substances not be kept in brass and copper vessels?
Curd contains which reacts with metals. When acids react with metals, they produce . When is stored in a copper container, the acid will react with the container, spoiling both the food and the container.
2. A metal compound reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.