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.
i) The transition metals appear to be unique in their ability to react with small atoms of non-metal to give interstitial compound. These metals form various interstitial compound in which small non- metal like H,C,B,N and He occupy the empty space in their lattice and also form bonds with them.
These new compounds are known as hydrides, carbides, borides, nitrides and halids respectively.
These interstial compound are hard and rigid. for example steel and cast iron which are interstitial compound of Fe and C are hard.
ii) Mn (Z = 25) = 3d5 4s2
Mn+2 is the most stable ion for manganese, the d-orbital can be made to remove 0 to 7 electrons. Compounds of manganese therefore range from Mn(0) as Mn(s), Mn(II) as MnO, Mn(II,III) as Mn3O4, Mn(IV) as MnO2, or manganese dioxide, Mn(VII) in the permanganate ion MnO4-, and so on. Mn has the maximum number of unpaired electrons present in the d-subshell (5 electrons). Hence, Mn exhibits the largest number of oxidation states, ranging from +2 to +7.
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?
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.
Switch
