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प्रश्न
Identify A to E and also explain the reactions involved.
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उत्तर
A = \[\ce{Cu}\]
B = \[\ce{Cu(NO3)2}\]
C = \[\ce{[Cu(NH3)4]}\]
D = \[\ce{CO2}\]
E = \[\ce{CaCO3}\]
F = \[\ce{Cu2[Fe(CN)6]}\]
G = \[\ce{Ca (HCO3)2}\]
\[\ce{CuCO3 -> CuO + CO2}\]
\[\ce{CuO + CuS -> \underset{(A)}{Cu} + SO2}\]
\[\ce{Cu + 4HNO3 (Conc) -> Cu \underset{(B)}{(NO3)2} + 2NO + 2H2O}\]
\[\ce{\underset{(B)}{Cu^2+} + NH3 -> \underset{(C)}{[Cu(NH3)4]}}\]
\[\ce{Ca(OH)2 + \underset{(D)}{CO2} -> \underset{(E)}{CaCO3} + H2O}\]
\[\ce{CaCO3 + CO2 + H2O -> Ca(HCO3)2}\]
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संबंधित प्रश्न
Which metal in the first transition series (3d series) exhibits + 1 oxidation state most frequently and why?
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Write the element which shows maximum number of oxidation states. Give reason.
What may be the stable oxidation state of the transition element with the following d electron configuration in the ground state of its atom?
3d3
What are the characteristics of the transition elements and why are they called transition elements?
In what way is the electronic configuration of the transition elements different from that of the non-transition elements?
For M2+/M and M3+/M2+ systems, the E° values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
- The stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+ and
- the ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
Account for the following :
Ti4+ is colourless whereas V4+ is coloured in an aqueous solutions.
In lake test for Al3+ ions, there is the formation of coloured ‘floating lake’. It is due to ______.
Read the passage given below and answer the following question:
The transition metals when exposed to oxygen at low and intermediate temperatures form thin, protective oxide films of up to some thousands of Angstroms in thickness. Transition metal oxides lie between the extremes of ionic and covalent binary compounds formed by elements from the left or right side of the periodic table. They range from metallic to semiconducting and deviate by both large and small degrees from stoichiometry. Since electron bonding levels are involved, the cations exist in various valence states and hence give rise to a large number of oxides. The crystal structures are often classified by considering a cubic or hexagonal close-packed lattice of one set of ions with the other set of ions filling the octahedral or tetrahedral interstices. The actual oxide structures, however, generally show departures from such regular arrays due in part to distortions caused by packing of ions of different size and to ligand field effects. These distortions depend not only on the number of d-electrons but also on the valence and the position of the transition metal in a period or group.
In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage.
Assertion: Transition metals form protective oxide films.
Reason: Oxides of transition metals are always stoichiometric.
Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d5. What is its atomic number?
When a brown compound of manganese (A) is treated with \[\ce{HCl}\] it gives a gas (B). The gas taken in excess, reacts with \[\ce{NH3}\] to give an explosive compound (C). Identify compounds A, B and C.
Assertion: Separation of \[\ce{Zr}\] and \[\ce{Hf}\] is difficult.
Reason: Because \[\ce{Zr}\] and \[\ce{Hf}\] lie in the same group of the periodic table.
Sodium this sulphate is used in photography because of its:-
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
Assertion (A): Transition metals have high enthalpy of atomisation.
Reason (R): Greater number of unpaired electrons in transition metals results in weak metallic bonding.
Assertion (A): Transition metals show their highest oxidation state with oxygen.
Reason (R): The ability of oxygen to form multiple bonds to metals.
The second ionization enthalpies of chromium and manganese are 1592 and 1509 kJ/mol respectively. Explain the lower value of Mn.
Give two similarities in the properties of Sc and Zn.
For M2+/M and M3+/M2+systems, the EΘ values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
The ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
