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प्रश्न
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iron (II) solution.
उत्तर
Potassium dichromate acts as a strong oxidizing agent. It is used as a primary standard in volumetric analysis. The oxidation action of dichromate ion in an acidic medium can be represented as follows –
\[\ce{Cr2O^{2-}_7 + 14H^+ + 6e^- -> 2Cr^{3+} + 7H2O}\] (E– = 1.33 V)
When ferrous salts (Fe2+) are treated with acidified K2Cr2O7, they are oxidised to ferric (Fe3+) salts.
\[\ce{Cr2O^{2-}_7 + 14H^+ + 6Fe^{2+} -> 2Cr^{3+} + 7H2O + 6Fe^{3+}}\]
संबंधित प्रश्न
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element has the highest m.p?
How would you account for the following: Transition metals form complex compounds.
How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
An antifriction alloy made up of antimony with tin and copper, which is extensively used in machine bearings is called _______.
(A) Duralumin
(B) Babbitt metal
(C) Spiegeleisen
(D) Amalgam
Match the properties given in Column I with the metals given in Column II.
| Column I (Property) | Column II (Metal) | |
| (i) | Element with highest second ionisation enthalpy |
(a) \[\ce{Co}\] |
| (ii) | Element with highest third ionisation enthalpy |
(b) \[\ce{Cr}\] |
| (iii) | \[\ce{M}\] in \[\ce{M(CO)6}\] is | (c) \[\ce{Cu}\] |
| (iv) | Element with highest heat of atomisation |
(d) \[\ce{Zn}\] |
| (e) \[\ce{Ni}\] |
Mention any three processes where transition metals act as catalysts.
It has been observed that first ionization energy of 5 d series of transition elements are higher than that of 3d and 4d series, explain why?
Which one among the following metals of the 3d series has the lowest melting point?
Give a reason for the following:
Transition metals possess a great tendency to form complex compounds.
