Violet colour of $[Ti(H_2O)_6]Cl_3$ on heating changes to $........$

Which of the following is the correct order in the spectrochemical series of ligands?

The stepwise formation of $[Cu(NH_{3})_{4}]^{2+}$ is given below:
$Cu^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})]^{2+} \quad K_{1}$
$[Cu(NH_{3})]^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})_{2}]^{2+} \quad K_{2}$
$[Cu(NH_{3})_{2}]^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})_{3}]^{2+} \quad K_{3}$
$[Cu(NH_{3})_{3}]^{2+} + NH_{3} \rightleftharpoons [Cu(NH_{3})_{4}]^{2+} \quad K_{4}$
The values of stability constants $K_{1}, K_{2}, K_{3}$ and $K_{4}$ are $10^{4}, 1.58 \times 10^{3}, 5 \times 10^{2}$ and $10^{2}$ respectively. The overall equilibrium constant for dissociation of $[Cu(NH_{3})_{4}]^{2+}$ is $x \times 10^{-12}$. The value of $x$ is ...............
(Rounded off to the nearest integer)

Which of the following cations forms the least stable complex with the same ligand?

Give the correct order of electrical conductivity of aqueous solution of the following complexes:
$A$. $[Pt(NH_3)_6]Cl_4$
$B$. $[Cr(NH_3)_6]Cl_3$
$C$. $[Co(NH_3)_4Cl_2]Cl$
$D$. $K_2[PtCl_6]$

The colour of $CoCl_3 \cdot 5NH_3 \cdot H_2O$ is