Science : Ch 03 – Metals and Non-metals

Prolong heating of red hot iron with steam forms Fe₃O₄ with hydrogen gas.

Ionic compounds are generally soluble in water and insoluble in solvents such as kerosene and petrol.

Aqua-regia is the mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1. Aqua-regia, being a strong acid, dissolves gold.

At room temperature, mercury (Hg) is the only metal found in liquid state.

Na (sodium) possesses all the above properties. It is too soft and can be cut with a knife.. It also reacts with water and burns due to the vigorously formation of hydrogen gas.

When pieces of copper metal are kept immersed in silver sulphate solution for some time, the solution moderately becomes blue and a shiny greyish-white deposit of silver metal is formed on copper strip

Element X is Sodium Aluminate. Al₂O₃ is chemically called aluminum oxide or we can say it is a metal oxide. Aluminum oxide shows basic as well as acidic behavior. Such metal oxides are called amphoteric oxides.

The hydrogen gas formed at the initial stage of reaction bubbles on the surface and makes magnesium ribbon lighter. Consequently it does not sink and float on water where as calcium and water are also less violent therefore calcium also floats on water.