Chapter 20

A solution containing \(2.675 \mathrm{~g}\) of \(\mathrm{CoCl}_{3} \cdot 6 \mathrm{NH}_{3}\) (molar mass \(=267.5 \mathrm{~g} \mathrm{~mol}^{-1}\) ) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of \(\mathrm{AgNO}_{3}\) to give \(4.78 \mathrm{~g}\) of \(\mathrm{AgCl}\) (molar mass \(\left.=143.5 \mathrm{~g} \mathrm{~mol}^{-1}\right) .\) The formula of the complex is (Atomic mass of \(\mathrm{Ag}=108 \mathrm{u}\) ) [2010] (a) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}\) (b) \(\left[\mathrm{CoCl}_{2}\left(\mathrm{NH}_{3}\right)_{4}\right] \mathrm{Cl}\) (c) \(\left[\mathrm{CoCl}_{3}\left(\mathrm{NH}_{3}\right)_{3}\right]\) (d) \(\left[\mathrm{CoCl}\left(\mathrm{NH}_{3}\right)_{5}\right] \mathrm{Cl}_{2}\)

The magnetic moment (spin only) of \(\left[\mathrm{NiCl}_{4}\right]^{2-}\) is: \(\quad[\mathbf{2 0 1 1}]\) (a) \(1.41 \mathrm{BM}\) (b) \(5.64 \mathrm{BM}\) (c) \(1.28 \mathrm{BM}\) (d) \(2.82 \mathrm{BM}\)

Which of the following facts about the complex \(\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}\) is wrong? [2011] (a) The complex gives white precipitate with silver nitrate solution. (b) The complex involves \(\mathrm{d}^{2} \mathrm{sp}^{3}\) hybridisation, and is octahedral in shape. (c) The complex is an outer orbital complex. (d) The complex is paramagnetic.

Which among the following will be named as dibromidobis (ethylene diamine) chromium (III) bromide? (a) \(\left[\mathrm{Cr}(\mathrm{en})_{2} \mathrm{Br}_{2}\right] \mathrm{Br}\) (b) \(\left[\mathrm{Cr}(\mathrm{en}) \mathrm{Br}_{2}\right] \mathrm{Br}\) (c) \(\left[\mathrm{Cr}(\mathrm{en})_{3}\right] \mathrm{Br}_{3}\) (d) \(\left[\mathrm{Cr}(\mathrm{en})_{2} \mathrm{Br}_{2}\right] \mathrm{Br}\)

The pair having same magnetic movement is [2016] (a) \(\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) and \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) (b) \(\left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)\right]^{2+}\) and \(\left.\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) (c) \(\left[\mathrm{CoCl}_{4}\right]^{2}\) and \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) (d) \(\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) and \(\left[\mathrm{CoCl}_{4}\right]^{2}\)

Which of the following complexe shows optical isomerism (a) \(\operatorname{Cis}\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}\) (b) \(\operatorname{trans}\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}\) (c) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl}\) (d) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{3} \mathrm{Cl}_{3}\right]\)