Advertisements
Advertisements
प्रश्न
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.
Advertisements
उत्तर
The oxidation potentials for Fe, Cr, and Mn are +0.4 V, +0.9 V, and +1.2 V, respectively. Hence, the order of ease of oxidation of these is Mn > Cr > Fe.
APPEARS IN
संबंधित प्रश्न
What are interstitial compounds?
Out of Mn3+ and Cr3+, which is more paramagnetic and why ?
(Atomic nos. : Mn = 25, Cr = 24)
Compare the stability of +2 oxidation state for the elements of the first transition series.
What are alloys?
An analysis shows that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reason.
Complete and balance the following chemical equations
`Fe^(2+) + MnO_4^(-) + H^+ ->`
The transition metals show _________ character because of the presence of unpaired· electrons and Cu+ is ____________ because of its electronic configuration is [Ar]3d10
Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.
Which is the most stable oxidation state of iron?
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.
Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds?
The orientation of an atomic orbital is governed by
On strong heating AgNO3, the gases evolved are:-
Which does not belong to first transition series?
Why are all copper halides known except that copper iodide?
In the ground state of atomic Fe (Z = 26), the spin-only magnetic moment is ______ × 10-1 BM.
(Round off to the nearest integer).
[Given: `sqrt3 = 1.73, sqrt2 = 1.41`]
Account for the following:
Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.
Account for the following:
Copper has an exceptionally positive `"E"_("M"^(2+)//"M")^0` value.
Give two similarities in the properties of Sc and Zn.
Explain the magnetic properties of d-block (or transition) elements.
