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प्रश्न
What are alloys?
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उत्तर
An alloy is a blend of metals prepared by mixing the components. Alloys may be homogeneous solid solutions in which the atoms of one metal are distributed randomly among the atoms of the other.
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संबंधित प्रश्न
Why do interstitial compounds have higher melting points than corresponding pure metals?
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
Account for the following:
Zn is not considered as a transition element.
Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?
How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iodide.
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 stability of Fe3+ in acid solution as compared to that of Cr3+ or Mn3+.
Compare the stability of +2 oxidation state for the elements of the first transition series.
Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.
Which of the following statements is not correct?
Transition elements show high melting points. Why?
Assertion: The highest oxidation state of osmium is +8.
Reason: Osmium is a 5d-block element.
Identify A to E and also explain the reactions involved.
Answer the following question:
Which element of the first transition series has lowest enthalpy of atomisation?
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
Catalytic hydrogenation of benzene gives
The complex showing a spin-span magnetic moment of 2.82 B.M. is :-
Why are all copper halides known except that copper iodide?
Assertion (A): Transition metals have high enthalpy of atomisation.
Reason (R): Greater number of unpaired electrons in transition metals results in weak metallic bonding.
What is the oxidation state of chromium in chromate ion and dichromate ion?
