Question

Choose the true statement regarding compounds X and Y :

• A. Both compounds X and Y have different magnetic moment (spin only)
• B. Both complexes X and Y have same magnetic moment (spin only)
• C. Magnetic moment of both X and Y is calculated by assuming they are low-spin complex.
• D. Both compounds X and Y have different primary valency.

Answer 1

Answer: (B)

Both complexes X and Y have same magnetic moment (spin only)

AgCl is a white precipitate and AgBr is a light yellow precipitate.

In complex $\left(X\right)$, $Cl$ must be outside of the coordination sphere because it is giving white ppt. with $AgN{O}_3$.

Hence,X = $\left[Cr\right(N{H}_3{)}_{4}ClBr]Cl$

In complex $\left(Y\right)$, $Br$ must be outside of the coordination sphere because it is giving yellow ppt. with $AgN{O}_3$.

Hence,Y = $\left[Cr\right(N{H}_3{)}_{4}C{l}_2]Br$

In both the complexes Cr is in +3 state.
Cr- $\left[Ar\right]3d^3$

Both the comlexes have same spin magnetic moment- $\sqrt{n(n+2)}BM=\sqrt{15}BM$

Hence, option $B$ is correct.