Test: MCQs (One or More Correct Option): The d- and f-Block Elements & Coordination Compounds | JEE Advanced - JEE MCQ

Aqueous solution of Co(NO₃)₂ and CrCl₃ in which Co²⁺ (d⁷) and Cr³⁺ (d³) contains incompletely filled d-orbitals are coloured.

Highest parmagnetic character will be shown by the ion having maximum number of unpaired electrons in their d-subshells.
₂₅Cr³⁺ has 3 unpaired electrons ; ₂₆Fe²⁺ has 4 unpaired electrons
₂₉Cu²⁺ has 1 unpaired electrons ; ₃₀Zn2+ has no unpaired electrons
So (a), (b) & (c) show paramagnetism. Out of which (b) has the highest paramagnetism.

Brass : Cu (60-80%), Zn (40-20%); Gun Metal : Cu (87%), Sn (10%), Zn (3%).

The magnetic moment (μ) of a species is related to its number of unpaired electrons (n) in form of following expressions.

The number of unpaired electrons in the given pairs are as follows:

The given combinations differ in the number of unpaired electrons. Hence these can be differentiated by the measurement on the solid state magnetic moment of nitroprusside ion.

Mn makes steel harder and increases its elasticity and tensile strength. Further Mn acts as deoxidiser.
MnO reacts with S present in cast iron, gets oxidised and then combine to form slag.

In Fe(CO)₅​ there exists a synergic bond between Fe and CO. Due to synergic bond formation between metal and CO, the bond order of CO decreases.

As bond order decreases the Bond length increases.Here the only option having greater bond length than 1.128A⁰ is option A 1.158A⁰.

In acidic medium

Change in oxidation state of Mn = 7 – 2 = 5

Thus electrons lost = 5
In neutral medium

Change in oxidation state of Mn = 7 – 4 = 3
∴ Electrons lost = 3

Cu²⁺ ions will react with CN^– and SCN^– forming [Cu(CN)₄]^3– and [Cu(SCN)₄]^3– leading the reaction in the backward direction.

Cu²⁺ also combines with CuCl₂ which reacts with Cu to produce CuCl pushing the reaction in the backward direction.

Th e pair of complex ion s [Co(NH₃)₄Cl₂]+ and [Pt(NH₃)₂(H₂O)Cl]+ show geometrical isomerism.
The pair of complexes [Pt(NH₃)₃(NO₃)]Cl and [Pt(NH₃)₃Cl]Br show ionisation isomerism. The other pairs given do not have same type of isomerism.

Na + NH₃ (excess) → Dilute solution of Na in liq.
NH₃ → Paramagnetic
K + O₂ (excess) → KO₂ (O₂^– is paramagnetic)
Cu + HNO₃ (dil.) → Cu(NO₃)₂ + NO (NO is paramagnetic) 2-Ethylanthraquinol + O2 →
2-Ethylanthraquinone + H₂O₂
(H₂O₂ is diamagnetic)

Cr²⁺ is a reducing agent and Mn³⁺ is an oxidizing agent and both have electronic configuration d⁴.

Above E° values explains reducing nature of Cr²⁺ and oxidizing behaviour of Mn³⁺.