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प्रश्न
Name an important alloy which contains some of the lanthanoid metals.
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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.
संबंधित प्रश्न
What are lanthanoids?
Account for the following :
Zr and Hf have almost similar atomic radii.
What are the different oxidation states exhibited by the lanthanoids?
The chemistry of the actinoid elements is not so smooth as that of the Lanthanoids. Justify this statement by giving some examples from the oxidation state of these elements.
Name the members of the lanthanoid series which exhibit +4 oxidation state and those which exhibit +2 oxidation state. Try to correlate this type of behavior with the electronic configurations of these elements.
Write the different oxidation states of iron
Account for the following:
Zn, Cd and Hg are soft metals.
Explain the cause of Lanthanoids contraction.
What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
What is Lanthanoid contraction?
The f-block elements are known as ____________.
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 |
Match the property given in Column I with the element given in Column II.
| Column I (Property) | Column II (Element) | |
| (i) | Lanthanoid which shows +4 oxidation state |
(a) Pm |
| (ii) | Lanthanoid which can show +2 oxidation state |
(b) Ce |
| (iii) | Radioactive lanthanoid | (c) Lu |
| (iv) | Lanthanoid which has 4f7 electronic configuration in +3 oxidation state |
(d) Eu |
| (v) | Lanthanoid which has 4f14 electronic configuration in +3 oxidation state |
(e) Gd |
| (f) Dy |
On the basis of Lanthanoid contraction, explain the following:
Radii of 4d and 5d block elements.
On the basis of Lanthanoid contraction, explain the following:
Trends in acidic character of lanthanoid oxides.
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.
Cerium (Z = S8) is an important member of lanthanoids. Which of the following statements about cerium is incorrect?
Why is Mn2+ ion more stable than Fe2+ ion?
(Atomic numbers of Mn = 25 and Fe = 26)
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
Assertion: There is a continuous increase in size among Lanthanoids with an increase in atomic number.
Reason: Lanthanoids do not show Lanthanoid contraction.
