The reaction of aqueous ${\left[\mathrm{Ni}{\left({\mathrm{H}}_{2}0\right)}_6\right]}^{2+}$ Is performed by the addition of a bidentate ligand ethane-1, 2, diamine (en)
Match the following

	${\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}:$ en molar ratio		Colour of the product
A	$1 : 1$	I	Pale blue
B	$1 : 2$	II	Blue / Purple
C	$1 : 3$	III	Violet
D		IV	Green

The correct match is

• Correct answer
  A

  A	B	C
  I	II	III

• B

  A	B	C
  II	III	IV

• C

  A	B	C
  III	I	II

  .
• D

  A	B	C
  IV	I	III

Hence, the correct answer is option: 'A'.