Explain the meanings of malleable and ductile.

Samples of four metals $A$,$B$,$C$ and $D$ were taken and added to the following solutions one by one. The results obtained have been tabulated as follows.

Metal	Iron $(II)$ sulphate	Copper $(II)$ sulphate	Zinc sulphate	Silver nitrate
$A$	No reaction	Displacement	No reaction	Displacement
$B$	Displacement	Displacement	No reaction	Displacement
$C$	No reaction	No reaction	No reaction	Displacement
$D$	No reaction	No reaction	No reaction	No reaction

Use the table above to answer the following questions about metals $A$,$B$,$C$ and $D$:
$(i)$ Which is the most reactive metal?
$(ii)$ What would you observe if $B$ is added to a solution of Copper $(II)$ sulphate?
$(iii)$ Arrange the metals $A$,$B$,$C$ and $D$ in the order of decreasing reactivity.

You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

Differentiate between metal and non-metal on the basis of their chemical properties.

Give an example of a metal which:
$(i)$ is a liquid at room temperature.
$(ii)$ can be easily cut with a knife.
$(iii)$ is the best conductor of heat.
$(iv)$ is a poor conductor of heat.

In the electrolytic refining of a metal $M$,what would you take as the anode,the cathode,and the electrolyte?