Which of the following has the highest molar conductivity in solution?

$A$ solution contains $2.675 \ g$ of $CoCl_3 \cdot 6NH_3$ $(M = 267.5 \ g/mol)$. When passed through a cation exchanger,the chloride ions liberated are treated with excess $AgNO_3$ to yield $4.78 \ g$ of $AgCl$ $(M = 143.5 \ g/mol)$. What is the formula of the coordination compound?

Which of the following represents the correct increasing order of the spectrochemical series (field strength) for some common ligands?

Which one is the most likely structure of $CrCl_3 \cdot 6H_2O$ if $1/3$ of total chlorine of the compound is precipitated by adding $AgNO_3$ to its aqueous solution?

An aqueous pink solution of Cobalt $(II)$ chloride changes to deep blue on addition of excess of $HCl$. This is because:

In $[Fe(CO)_5]$,the $Fe-C$ bond has