The correct order of solubility in water is:

Choose the correct statement and mark the correct option given below:
$(a)$ $AgF$ is soluble and colourless in aqueous medium.
$(b)$ For $LiF$,solubility and melting point are both lower as compared to $NaF$.
$(c)$ Solubility of $Rb_2SO_4$ is less as compared to $BaSO_4$.
$(d)$ If $AgI$ is added to water,the colour of water will turn yellow from colourless.

To distinguish between $A$ and $B$,it is observed that both elements form oxides,but $B$ also forms a nitride when burnt in air. What are $A$ and $B$?

Which of the following mixtures is known as fusion mixture?

Copper becomes green when exposed to moist air for a long period. This is due to

Copper is very slowly oxidized on the surface in moist air,giving a green coating of verdigris. The chemical formula of verdigris is: