An aqueous solution of ${\rm{CoC}}{{\rm{l}}_2}$ on addition of excess of concentrated ${\rm{HCl}}$ turns blue to formation of

${\left[ {{\rm{CoC}}{{\rm{l}}_4}} \right]^{2 - }}$

${\left[ {{\rm{Co}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_2}{\rm{C}}{{\rm{l}}_4}} \right]^{2 - }}$

${\left[ {{\rm{Co}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_2}2{\rm{C}}{{\rm{l}}_4}} \right]^{2 - }}$

$\left[ {{\rm{Co}}{{\left( {{{\rm{H}}_2}{\rm{O}}} \right)}_4}{\rm{C}}{{\rm{l}}_2}} \right]$

NEET UG CHEMISTRY MCQ: CO-ORDINATION COMPOUNDS

1 Hard

1 of 1

Understanding +4 | -1

An aqueous solution of

\mathrm{CoC}{\mathrm{l}_2}

on addition of excess of concentrated

\mathrm{HCl}

turns blue to formation of

View answer and explanation

Correct option: A

{\left[ {\mathrm{CoC}{\mathrm{l}_4}} \right]^{2 - }}

Option A (

{\left[ {\mathrm{CoC}{\mathrm{l}_4}} \right]^{2 - }}

) is correct because the addition of excess concentrated HCl to an aqueous solution of

\mathrm{CoC}{\mathrm{l}_2}

leads to the formation of the tetrahedral complex

{\left[ {\mathrm{CoC}{\mathrm{l}_4}} \right]^{2 - }}

which is blue in color.