Short Answer TypeDistinguish between paramagnetism and ferro-magnetism. How does ferro magnetism arise?
Long Answer Type(i) Breifly explain the physical properties of lanthanoids.
(ii) The chemical reactivity of lanthanoids resembles to which other elements of the periodic table.
Short Answer TypeHow does the acidified KMnO4 react with the following:
(a) Iron(II) solution, (b)SO32–, (c) Iodide (I–) ion, (d) oxalic acid, (e) NO2– (Nitrite ion).
Long Answer TypeExplain any one of following statement:
(i) The transition metals are well known for the formation of interstitial compounds.
(ii) The largest number of oxidation states are exhibited by mangnese in the first series of transition elements.
Short Answer TypeAnswer the following questions:
(i) Which element in the first series of transition elements does not exhibit variable oxidation states and why?
(ii) Why do actinoids in general exhibit a greater range of oxidation states than the Lanthanoids?
i) The ability of the transition metals to exhibit variable valency is generally attributed to the availability of more electrons in the (n-1)d orbitals which are closer to the outermost ns orbital in energy levels.
Scandium and zinc does not show variable oxidation states.
ii) Lanthanoids primarily show three oxidation states (+2, +3, +4). Among these oxidation states, +3 state is the most common. Lanthanoids display a limited number of oxidation states because the energy difference between 4f, 5d, and 6s orbitals is quite large. On the other hand, the energy difference between 5f, 6d, and 7s orbitals is very less. Hence, actinoids display a large number of oxidation states. For example, uranium and plutonium display +3, +4, +5, and +6 oxidation states while neptunium displays +3, +4, +5, and +7. The most common oxidation state in case of actinoids is also +3.
Long Answer Typei)Describe how potassium permanganate is made from pyrolusite. Write the chemical equations for the involved reactions.
ii) Describe with an example each of the oxidising actions of permanganate ion in alkaline and acidic media. What acid and alkali are usually used?
Describe how potassium dichromate is made from chromate ore and give the equations for the chemical reactions involved.
Write balanced ionic equations for reacting ions to represent the action of acidified potassium dichromate solution on:
(a) Potassium iodide solution.
(b) Acidified ferrous sulphate solution. Write two uses of potassium dichromate.
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