11Ans 1) (a) ????
hopeless chem questions
Q1. Choose the incorrect statement
(a) In [Fe(CN)6]4- , Fe-C bond length is smaller than Fe-C bond length in [Fe(CN)6]3-
(b) EAN of Fe in [Fe(CN)6]4- is 36
(c) [Fe(CN)6]3- is more stable than [Fe(CN)6]4-
(d) [Fe(Phen)3]3+ is more stable than [Fe(Phen)3]2+
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16 Answers
11EAN Stands for Effective Atomic Number
http://www.britannica.com/EBchecked/topic/179961/effective-atomic-number
Anywyas, EAN also stands for European Article Number, but that isn't in the syllabus of JEE (obviously) [8][6]
6yeah if nyone knos abt dis thn pls helppp........
6@ashish one question.y do u cl dis question hopeless??
1When a complex is formed,ligands are added till the sum of electrons donated by the ligands and those present on the central atom/ion became equal to the electrons in the next noble gas.Most of the complex entities obey this rule.However there are many compounds that defy this rule.
EAN can be calculated by the following relationship:
EAN=Z(metal atom)-O.N. of metal + 2*C.N.
Like in [Fe(CN)6]4-, the EAN will be = (26) - (+2) + 2x6 =36, which gives a stable gas configuration hence it is considered more stable. Whereas for [Fe(CN)6]3-, the EAN comes out to be 35 and hence is not stable.
29Though EAN rule helps to predict whether the complex is stable or not...but it has many exceptions as in this case [Fe(CN)6]3- is more stable than [Fe(CN)6]2- ..
well this is just experimentally detected..
Fe-C bond length in [Fe(CN)6]3- is smaller than that in [Fe(CN)6]2-
1option (a) is correct
it follows the following concept.........
when C makes bond with N, it forms a single bond and two pi bonds....
for pi bonds we have empty pi* ABMO, which has same symmetry as of d-orbitals.......so if there is any electron density in d-orbitals, i.e., negative charge on the metal or least positive charge, then central metal can donate electron density into empty pi* therefore it forms partial double bond and hence decrease in bond length is observed..........
this is wat exactly happning in de case of Fe3+ and Fe2+...later has low positive charge hence greater ability to donate, compared to former...........