A substance was burnt in air. The white residue obtained was added to water. This water solution turned red litmus into blue. State whether the substance is a metal or a non-metal?

24 Some non-metals like phosphorus are kept in water to protect them from atmospheric oxygen. State the property of the non-metals utilized here. 25 Why should foodstuffs with acid component not be stored in metallic containers? 27 An oxide solution of which of the following elements will turn blue litmus red? Calcium sulphur iron sodium. 28 Name a metal that is not attacked by cold water, boiling water or steam.