NEETChemistryCoordination Compounds
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The ligand SCN ^- produces a smaller crystal field splitting ( _o ) than the ligand NCS ^- when forming complexes with the same metal ion. Reason (R): In SCN ^- , the donor atom is sulphur, whereas in NCS ^- , the donor atom is nitrogen, which generally acts as a stronger field donor. In the light
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- C(A) is true but (R) is false
- D(A) is false but (R) is true
Correct answer
A. Both (A) and (R) are true and (R) is the correct explanation of (A)
Step-by-step solution
According to the spectrochemical series, the ligand field strength of SCN ^- is less than that of NCS ^- . Thus, SCN ^- produces a smaller crystal field splitting ( _o ) than NCS ^- . Hence, Assertion (A) is true. The ambidentate ligand thiocyanate can coordinate through either the sulphur atom ( SCN ^- ) or the nitrogen atom ( NCS ^- ). Nitrogen is generally a stronger field donor than sulphur, which explains why NCS ^- causes a larger crystal field splitting than SCN ^- . Hence, Reason (R) is true and is the corr