The shape of pentacarbonyl iron,$Fe(CO)_5$,is:

Assertion : $[FeF_6]^{3-}$ is a low spin complex.
Reason : Low spin complexes have a lesser number of unpaired electrons.

Write the limitations of Valence Bond Theory $(VBT)$.

Statement $1$: $[Ti(H_2O)_6]^{4+}$ is coloured while $[Sc(H_2O)_6]^{3+}$ is colourless.
Statement $2$: $d-d$ transition is not possible in $[Sc(H_2O)_6]^{3+}$.

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A. Ni(CO)_4$	$I. sp^3$
$B. [Ni(CN)_4]^{2-}$	$II. sp^3d^2$
$C. [Co(CN)_6]^{3-}$	$III. d^2sp^3$
$D. [CoF_6]^{3-}$	$IV. dsp^2$

Choose the correct answer from the options given below.

The number of unpaired electrons in $[Co(NH_3)_6]^{3+}$ and $[CoF_6]^{3-}$ are respectively.....