NEETChemistryCoordination Compounds
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R . Assertion A: The spin only magnetic moment value for Fe ( CN ) 6 3 - is 1 . 74 BM , whereas for [Fe(H2O)6] Fe H 2 O 6 3 + is 5 . 92 BM . Reason B: In both complexes, Fe is present in + 3 oxidation state. In the light of the above statements, choose the correct answer from the options given below:
Options
- AA is false but R is true
- BA is true but R is false
- CBoth A and R are true but R is NOT the correct explanation of A
- DBoth A and R are true and R is the correct explanation of A
Correct answer
C. Both A and R are true but R is NOT the correct explanation of A
Step-by-step solution
[ Fe ( H 2 O ) 6 ] 3 + has magnetic moment value of 5 . 92 BM because H 2 O is a weak ligand and pairing will not occur. It involves sp 3 d 2 hybridisation with five unpaired electrons (because magnetic moment is equal to 5 . 92 BM ) and outer orbital complex is formed. Magnetic moment can be calculated by the formula μ m = n ( n + 2 ) BM where, μ m = magnetic moment, n = number of unpaired electron(s). μ m = 1 . 74 BM , n = 1 μ m = 5 . 92 BM , n = 5 In [ Fe ( CN ) 6 ] 3 – complex CN − is stronger ligand than H 2 O