Question

The correct increasing order of trans-effect of the following species is

• A. $N{H}_3>C{N}^{-}>B{r}^{-}>C_6{H}_5^{-}$
• B. $C{N}^{-}>C_6{H}_5^{-}>B{r}^{-}>N{H}_3$
• C. $B{r}^{-}>C{N}^{-}>N{H}_3>C_6{H}_5^{-}$
• D. $C{N}^{-}>B{r}^{-}>C_6{H}_5^{-}>N{H}_3$

Answer 1

The correct option is B $C{N}^{-}>C_6{H}_5^{-}>B{r}^{-}>N{H}_3$

Trans effect is the effect of a coordinated group upon the rate of substitution at the position trans to itself in a square or octahedral complex. As the rate of substitution of the trans ligand increases, the intensity of trans effect also increases. Thus, correct order is,
$C{N}^{-}>C_6{H}_5^{-}>B{r}^{-}>N{H}_3$