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प्रश्न
Match the properties given in Column I with the metals given in Column II.
| Column I (Property) | Column II (Metal) | |
| (i) | An element which can show +8 oxidation state | (a) \[\ce{Mn}\] |
| (ii) | 3d block element that can show | (b) \[\ce{Cr}\] |
| upto +7 oxidation state | (c) \[\ce{Os}\] | |
| (iii) | 3d block element with highest melting point | (d) \[\ce{Fe}\] |
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उत्तर
| Column I (Property) | Column II (Metal) | |
| (i) | An element which can show +8 oxidation state | (c) \[\ce{Os}\] |
| (ii) | 3d block element that can show upto +7 oxidation state |
(a) \[\ce{Mn}\] |
| (iii) | 3d block element with highest melting point | (b) \[\ce{Cr}\] |
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संबंधित प्रश्न
How would you account for the following?
Transition metals exhibit variable oxidation states.
Why +2 oxidation state of manganese is more stable?
Account for the following:
Cu+2 salts are coloured, while Zn2+ salts are white.
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?
Account for the following:
Zn is not considered as a transition element.
In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?
To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.
Compare the stability of +2 oxidation state for the elements of the first transition series.
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
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
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: Cations of transition elements occur in various valence states.
Reason: Large number of oxides of transition elements are possible.
Although Zirconium belongs to 4d transition series and Hafnium to 5d transition series even then they show similar physical and chemical properties because ______.
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
The orientation of an atomic orbital is governed by
The standard electrode potentials of four elements A, B, C and D are – 3.05, – 1.66, – 0.40 and + 0.80. The highest chemical reactivity will be exhibited by
On adding NaOH, solution to the aqueous solution of K2CrO7 the colour of the solution changes from
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iron (II) solution.
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.
