Formation of which complex, among the following, is not a confirmatory test of ${\mathrm{Pb}}^{2+}$ ions

A mixture of two salts is used to prepare a solution $\mathrm{S},$ which gives the following results:

$\mathrm{White} \mathrm{precipitate}\left(\mathrm{s}\right) \mathrm{only}\underset{\mathrm{Room} \mathrm{temperature}}{\overset{\mathrm{Dilute} \mathrm{NaOH}\left(\mathrm{aq}\right)}{\leftarrow }}\underset{\left(\mathrm{aq}. \mathrm{solution} \mathrm{of} \mathrm{the} \mathrm{salts}\right)}{\mathrm{S}}\underset{\mathrm{Room} \mathrm{temperature}}{\overset{\mathrm{Dilute} \mathrm{HCl}\left(\mathrm{aq}\right)}{\to }}\mathrm{White} \mathrm{precipitate}\left(\mathrm{s}\right) \mathrm{only}$

The correct option $\left(\mathrm{s}\right)$ for the salt mixture is(are)

State one relevant observation for of the following:

Lead nitrate solution is treated with sodium hydroxide solution dropwise till it is in excess.

Read the following sequence of reactions:

What are the compounds $\mathrm{D}$ and $\mathrm{E}$?

Hydroxide of this metal is soluble in sodium hydroxide solution: 

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 $100\}$

Identify $\mathrm{A}$ and $\mathrm{B}$.

$\mathrm{A}+\mathrm{NaOH}⟶{\mathrm{Na}}_2{\mathrm{SnO}}_2+{\mathrm{H}}_2$
$\mathrm{B}+\mathrm{NaOH}⟶{\mathrm{Na}}_2{\mathrm{PbO}}_2 + {\mathrm{H}}_2\mathrm{O}$

A solution of a salt gives a precipitate on treatment with dilute HCl. The precipitate formed is filtered off and treated with NH₃ whereby it turns black. The cation present in the salt is