Write down the number of 3d electrons in each of the following ions:
Ti2+, V2+, Cr3+, Mn2+, Fe2+, Fe3+, CO2+, Ni2+ and Cu2+.
Indicate how would you expect the five 3d orbitals to be occupied for these hydrated ions (octahedral).
Metal ion |
Number of d-electrons |
Filling of d-orbitals |
Ti2+ | 2 | t22g |
V2+ | 3 | t32g |
Cr3+ | 3 | t32g |
Mn2+ | 5 | t32g e2g |
Fe2+ | 6 | t42g e2g |
Fe3+ | 5 | t32g e2g |
CO2+ | 7 | t52g e2g |
Ni2+ | 8 | t62g e2g |
Cu2+ | 9 | t62g e3g |
Explain why Cu+ ion is not stable in aqueous solutions?
Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?
The Eθ(M2+/M) value for copper is positive (+0.34V). What is possibly the reason for this? (Hint: consider its high ΔaHV and low ΔhydHV)
How would you account for the following:
(i) Of the d4 species, Cr2+ is strongly reducing while manganese (III) is strongly oxidising.
(ii) Cobalt (II) is stable in aqueous solution but in the presence of complexing reagents it is easily oxidised.
(iii) The d1 configuration is very unstable in ions.
Actinoid contraction is greater from element to element than lanthanoid contraction. Why?
Which is a stronger reducing agent Cr2+ or Fe2+ and why?
Explain giving reasons:
(i) Transition metals and many of their compounds show paramagnetic behaviour.
(ii) The enthalpies of atomisation of the transition metals are high.
(iii) The transition metals generally form coloured compounds.
(iv) Transition metals and their many compounds act as good catalyst.
Give examples and suggest reasons for the following features of the transition metal chemistry:
(i)The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.
(ii)A transition metal exhibits highest oxidation state in oxides and fluorides.
(iii) The highest oxidation state is exhibited in oxoanions of a metal.
Predict which of the following will be coloured in aqueous solution?
Ti3+, V3+, Cu+, Sc3+, Mn2+, Fe3+ and Co2+.
Give reasons for each.
Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.
Write the formulas for the following coordination compounds:
(i) Tetraamminediaquacobalt (III) chloride
(ii) Potassium tetracyanonickelate(II)
(iii) Tris(ethane-1,2-diamine) chromium(III) chloride
(iv) Amminebromidochloridonitrito-N-platinate(II)
(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate
(vi) Iron(III) hexacyanoferrate(II)
(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
Why are solids rigid?
Write any two characteristics of Chemisorption.
Write the structures of the following compounds.
(i) α-Methoxypropionaldehyde
(ii) 3-Hydroxybutanal
(iii) 2-Hydroxycyclopentane carbaldehyde
(iv) 4-Oxopentanal
(v) Di-sec-butyl ketone
(vi) 4-Fluoroacetophenone
Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?
Why are pentahalides more covalent than trihalides?
Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
Write structures of the following compounds:
(i) 2-Chloro-3-methylpentane
(ii) 1-Chloro-4-ethylcyclohexane
(iii) 4-tert. Butyl-3-iodoheptane
(iv) 1,4-Dibromobut-2-ene
(v) 1-Bromo-4-sec. butyl-2-methylbenzene
Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.
Given the standard electrode potentials,
K+/ K = - 2.93V,
Ag+/ Ag = 0.80V,
Hg2+ / Hg = 0.79V
Mg2+ / Mg = - 2.37 V,
Cr3+ / Cr = - 0.74V
Arrange these metals in their increasing order of reducing power.
Write structural formulas and names of four possible aldol condensation products from propanal and butanal. In each case, indicate which aldehyde acts as nucleophile and which as electrophile.
What is the two dimensional coordination number of a molecule in square close packed layer?
What are artificial sweetening agents? Give two examples.
A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is
(i) doubled
(ii) reduced to half?
Why is helium used in diving apparatus?
'Stability of a crystal is reflected in themagnitude of its melting point'. Comment. Collect melting points of solid water, ethyl alcohol, diethyl ether and methane from a data book. What can you say about the intermolecular forces between these molecules?
What type of solids are electrical conductors, malleable and ductile?
The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 Scm-1. Calculate its molar conductivity.