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प्रश्न
Why do interstitial compounds have higher melting points than corresponding pure metals?
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उत्तर
The melting points of interstitial compounds are higher than those of pure metals because of bonding between the metal and the non-metal, which is stronger than metal–metal bonding.
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संबंधित प्रश्न
Which of the following cations are coloured in aqueous solutions and why ?
Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)
Account for the following:
Cu+2 salts are coloured, while Zn2+ salts are white.
How would you account for the following : Transition metals form coloured compounds
How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?
What are the characteristics of the transition elements and why are they called transition elements?
Compare the stability of +2 oxidation state for the elements of the first transition series.
Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.
Which one of the following ions is coloured?
Write balanced chemical equations for the conversion of `CrO_4^(2-)` to `Cr_2O_7^(2-)` in acidic medium and `Cr_2O_7^(2-)` to `CrO_4^(2-)`
in basic medium.
Complete and balance the following chemical equations
`Fe^(2+) + MnO_4^(-) + H^+ ->`
Complete and balance the following chemical equations
`MnO_4^(-) + H_2O + I^(-) ->`
Give reasons Iron has the higher enthalpy of atomization than that of copper.
Give reasons for the following:
The transition metals generally form coloured compounds.
Transition metals with lowest melting point is ______.
Maximum oxidation state is shown by ____________.
When an oxide of manganese (A) is fused with KOH in the presence of an oxidising agent and dissolved in water, it gives a dark green solution of compound (B). Compound (B) disproportionates in neutral or acidic solution to give purple compound (C). An alkaline solution of compound (C) oxidises potassium iodide solution to a compound (D) and compound (A) is also formed. Identify compounds A to D and also explain the reactions involved.
Mention any three processes where transition metals act as catalysts.
On the basis of the figure given below, answer the following questions:
- Why Manganese has lower melting point than Chromium?
- Why do transition metals of 3d series have lower melting points as compared to 4d series?
- In the third transition series, identify and name the metal with the highest melting point.
A metallic ion 'M' reacts with chloride ion to form white precipitate which is readily soluble in aqueous ammonia. Identify 'M'?
The electrode potential of M2+/M of 3d-series elements shows the positive value for ______.
The value of Δ0 for \[\ce{RhCl^{3-}6}\] is 243 KJ/mol which wavelength of light will promote an electron from. The colour of the complex is ______.
Which of the following ions acts as a typical transition metal ion?
Assertion (A): Transition metals show their highest oxidation state with oxygen.
Reason (R): The ability of oxygen to form multiple bonds to metals.
Which property of transition metals enables them to behave as catalysts?
The given graph shows the trends in melting points of transition metals:
Explain the reason why Cr has the highest melting point and manganese (Mn) has a lower melting point.
In order to protect iron from corrosion, which one will you prefer as a sacrificial electrode, Ni or Zn? Why? (Given standard electrode potentials of Ni, Fe and Zn are -0.25 V, -0.44 V and -0.76 V respectively.)
Explain the use of different transition metals as catalysts.
Give a reason for the following.
Some transition metals and their compounds get attracted towards the magnetic field.
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Atomic sizes
