What would be the observations when aqueous ammonia is added to a solution of zinc nitrate (until in excess) and heated?

Name the following:

A salt whose solution gives a white precipitate which is soluble in excess of $\mathrm{NaOH} \mathrm{or} {\mathrm{NH}}_4\mathrm{OH}$.

Name the following:

A metallic hydroxide which is insoluble in caustic soda but soluble in excess of ammonium hydroxide. 

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$