Ru belongs to the 4d series of elements and ethylene diamine(en) is a chelating ligand which causes a larger splitting in the 4d orbitals. This leads to a pairing of electrons in the orbital due to which the electronic configuration is

is a weak field ligand which is unable to cause pairing in
and hence the
configuration is accomodated as

Therefore, Option 3 is correct.
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5 g of Na2SO4 was dissolved in x g of H2O. The change in freezing point was found to be 3.820C. If Na2SO4 is 81.5% ionised, the value of x (K

A capacitor is made of two square plates each of side 'a' making a very small angle
A solution of m-chloroaniline, m-chlorophenol and m-chlorobenzoic acid in ethyl acetate was extracted initially with a saturated solution of NaHCO3 to give fraction A. The leftover organic phase was extracted with d