Which of the following complexes formed by Cu⁺⁺ ions is most stable?

The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of the wavelength of light in the visible region for the complexes?

\(1. \ \left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}>\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}>\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+} \\ 2. \ \left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}>\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}>\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+} \\ 3. \ \left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}>\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}>\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-} \\ 4. \ \left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}>\left[\mathrm{Co}(\mathrm{CN})_{6}\right]^{3-}>\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\)

The CFSE for octahedral${\left[\mathrm{ \; C}oC{l}_6\right]}^{4-}$ is 18,000 cm${}^{-1}$ . The CFSE for tetrahedral will be \(\mathrm{CoCl}_4{ }^{2-}\):${\left[\right]}^{}$\(\mathrm{CoCl}_4{ }^{2-}\)

1. 6000 cm${}^{-1}$

2. 16,000 cm${}^{-1}$

3. 18,000 cm${}^{-1}$

4. 8,000 cm${}^{-1}$

Atomic number of Mn Fe and Co are 25, 26 and 27 respectively. Which of the following inner orbital octahedral complex ions are diamagnetic?

a. ${\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]}^{3+}$

b. ${\left[\mathrm{Mn}{\left(\mathrm{CN}\right)}_6\right]}^{3-}$

c.  ${\left[Fe{\left(CN\right)}_6\right]}^{4-}$

d.  ${\left[\mathrm{Fe}{\left(CN\right)}_6\right]}^{3-}$

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)

Identify the outer orbital octahedral complexes among the following that have the same number of unpaired electrons:
(Atomic numbers of Mn, Fe, Co, and Ni are 25, 26, 27, and 28 respectively)

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)

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

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)

Match the complex ions give in Column I with the colours given in column II and assign the correct code.

Codes:

 Match the complex ions given in Column I with the hybridization and number of unpaired electrons given in Column II and assign the correct code. 

Codes: