What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of their atoms :
3d3, 3d5, 3d8 and 3d4?
Electronic configuration in ground state | Stable oxidation states | |
(i) |
3d3 (Vanadium) |
+2, +3, +4 and +5 |
(ii) |
3d5 (Chromium) |
+3, +4, +6 |
(iii) |
3d5 (Manganese) |
+2, +4, +6, +7 |
(iv) |
3d8 (Cobalt) |
+2, +3 |
(v) |
3d4 |
There is no3d4 configuration in ground state. |
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
Calculate the potential of hydrogen electrode in contact with a solution whose pH is 10.
Complete each synthesis by giving missing starting material, reagent or products
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Non-stoichiometric cuprous oxide, Cu2O can be prepared in laboratory. In this oxide, copper to oxygen ratio is slightly less than 2:1. Can you account for the fact that this substance is a p-type semiconductor?
What are essential and non-essential amino acids? Give two examples ofeach type.
Explain why is ortho nitrophenol more acidic than ortho methoxyphenol?
How are vitamins classified? Name the vitamin responsible for thecoagulation of blood.
Write equations of the following reactions:
(i) Friedel-Crafts reaction-alkylation of anisole.
(ii) Nitration of anisole.
(iii) Bromination of anisole in ethanoic acid medium.
(iv) Friedel-Craft's acetylation of anisole.
Henry's law constant for CO2 in water is 1.67 x 108Pa at 298 K. Calculate the quantity of CO2in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298 K.
Write chemical reaction of aniline with benzoyl chloride and write the name of the product obtained.
Complete the following reactions:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
How do we get to know this answer. I mean what is the explanation of this answer?