Question

The oxidation states of $Cr$ in $[Cr(H_2O)_6]Cl_3, [Cr(C_6H_6)_2]$, and $K_2[Cr(CN)_2(O)_2(O_2)(NH_3)]$ respectively are :

• A. +3, +4, and +6
• B. +3, +2, and +4
• C. +3, 0, and +6
• D. +3, 0, and +4

Answer 1

Answer: (C)

+3, 0, and +6

Answer 2

$\left[ Cr \left( H _{2} O \right)_{6}\right] Cl _{3}$
$\Rightarrow x +0 \times 6-1 \times 3=0$
$\therefore x =+3$
$\left[ Cr \left( C _{6} H _{6}\right)_{2}\right]$
$\Rightarrow x +2 \times 0=0$
$x =0$
$K _{2}[ Cr \left.( CN )_{2}\left( O _{2}\right)\left( O _{2}\right) NH _{3}\right]$
$\Rightarrow 1 \times 2+ x -1 \times 2-2 \times 2-2 \times 1=0$
$\Rightarrow x -6=0$
$x =+6$