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प्रश्न
Name an important alloy which contains some of the lanthanoid metals. Mention its uses.
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उत्तर
Misch metal is an alloy that contains some lanthanoid metals. It contains 95% lanthanoid metals, 5% iron and traces of S, C, Ca and Al. Misch metal is used in Mg-based alloys to produce bullets, shells, and lighter flint. It is used as a reducing agent in metallurgical operations. Magnesium alloys containing about 30% misch metal and 1% Zr are used for making parts of a jet engine
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संबंधित प्रश्न
Define lanthanoid contraction.
Account for the following :
Zr and Hf have almost similar atomic radii.
Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.
Write the different oxidation states of iron
Name an element of lanthanoid series which is well knwon to shown +4 oxidation state. Is it a strong oxidising agent or reducing agent?
What is lanthanoid contraction?
General electronic configuration of actinoids is `(n-2)f^(1-14)(n - 1)d^(0-2)ns^2`.Which of the following actinoids have one electron in 6d orbital?
(i) U (Atomic no. 92)
(ii) Np (Atomic no.93)
(iii) Pu (Atomic no. 94)
(iv) Am (Atomic no. 95)
Which of the following lanthanoids show +2 oxidation state besides the characteristic oxidation state +3 of lanthanoids?
(i) \[\ce{Ce}\]
(ii) \[\ce{Eu}\]
(iii) \[\ce{Yb}\]
(iv) \[\ce{Ho}\]
Although +3 oxidation states is the characteristic oxidation state of lanthanoids but cerium shows +4 oxidation state also. Why?
Match the compounds/elements given in Column I with uses given in Column II.
| Column I (Compound/element) | Column II (Use) | |
| (i) | Lanthanoid oxide | (a) Production of iron alloy |
| (ii) | Lanthanoid | (b) Television screen |
| (iii) | Misch metal | (c) Petroleum cracking |
| (iv) | Magnesium based alloy is constituent of | (d) Lanthanoid metal + iron |
| (v) | Mixed oxides of lanthanoids are employed | (e) Bullets |
| (f) In X-ray screen |
On the basis of Lanthanoid contraction, explain the following:
Nature of bonding in \[\ce{La2O3}\] and \[\ce{Lu2O3}\] .
On the basis of Lanthanoid contraction, explain the following:
Trends in the stability of oxo salts of lanthanoids from \[\ce{La}\] to \[\ce{Lu}\].
On the basis of Lanthanoid contraction, explain the following:
Trends in acidic character of lanthanoid oxides.
How would you account for the following:
There is a greater range of oxidation states among the actinoids than among the lanthanides.
State a reason for the following:
La(OH)3 is more basic than Lu(OH)3.
Why is Mn2+ ion more stable than Fe2+ ion?
(Atomic numbers of Mn = 25 and Fe = 26)
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
Name an important alloy which contains some of the lanthanoid metals.
