Question

Which of the following complexes is not expected to exhibit optical isomerism ?

• A. $\left[Co\right(en{)}_{2}C{l}_2{]}^{⨁}$
• B. $\left[Co\right(N{H}_3{)}_{3}C{l}_3]$
• C. $\left[Co\right(en\left)\right(N{H}_3{)}_{2}C{l}_2{]}^{⨁}$
• D. $\left[Co\right(en{)}_3{]}^{3+}$

Answer 1

The correct option is B

$\left[Co\right(N{H}_3{)}_{3}C{l}_3]$

$\left[Co\right(N{H}_3{)}_{3}C{l}_3]i.e.,M{a}_3{b}_3$ type exists in two geometrical forms (facial and meridional)

Both of these are achiral. Hence (b) does not show optical isomerism.

Note: $M(aa{)}_2{b}_2$, $M\left(aa\right)b_2{c}_{2}andM(aa{)}_3$ types show optical isomerism.

But $M{a}_4{b}_{2}orM{a}_2{b}_4$ type shown only geometrical isomers.