Question

A small amount of copper oxide was taken in a beaker and dilute hydrochloric acid was added with continuous stirring of the solution. Name the compound formed and state the colour of its solution. Write balanced chemical equation for the reaction that occurs. Based on the reaction, state the nature (acidic/basic) of copper oxide.

Sodium metal is stored under kerosene oil. Why ?

Some metal oxides are soluble in water. What are the aqueous solutions of these oxides called ? Write one example of such a solution.

At ordinary temperature the surface of metals such as magnesium, aluminium, zinc etc. is covered with a thin layer. What is the composition of this layer ? State its importance.