An aqueous solution of $FeSO_4$ gives tests for both $Fe^{2+}$ and $SO_4^{2-}$ ions,but after the addition of an excess of $KCN$,the solution ceases to give a test for $Fe^{2+}$. This is due to the formation of:

Which of the following ligands does not act as a $\pi$-acid ligand?

Which of the following compounds after mixing cannot produce blue coloration?

When aqueous sodium hydroxide is added to an aqueous solution of chromium $(III)$ ions,a green-blue precipitate is first formed which re-dissolves to give a green solution. This green colour is due to

Given below are two statements:
Statement $I$ : $N(CH_3)_3$ and $P(CH_3)_3$ can act as ligands to form transition metal complexes.
Statement $II$: As $N$ and $P$ are from same group,the nature of bonding of $N(CH_3)_3$ and $P(CH_3)_3$ is always same with transition metals.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which one of the following has the highest molar conductivity?