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प्रश्न
What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
उत्तर
- Action of water on lanthanoids: Reaction of water with lanthanoids gives ionic and basic lanthanide hydroxides (Ln(OH)3) with liberation of H2 gas.
Ln + 3H2O → Ln(OH)3 + 3H2 - Action of sulphur on lanthanoids: Heating of sulphur with
lanthanoids gives lanthanide sulphide (Ln2S3). - Action of nitrogen on lanthanoids: Reaction of nitrogen with lanthanoide gives lanthanide nitride (LnN).
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संबंधित प्रश्न
What are chemical twins? Write ‘two’ examples.
Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
What are the different oxidation states exhibited by the lanthanoids?
Compare the chemistry of actinoids with that of the lanthanoids with special reference to chemical reactivity.
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 electronic configurations of the elements with the atomic numbers 61, 91, 101 and 109.
Write the different oxidation states of iron
Explain effects of lanthanoid contraction
Explain the cause of lanthanoid contraction?
What is Lanthanoid contraction?
Explain the cause of Lanthanoids contraction.
Although +3 is the characteristic oxidation state for lanthanoids but cerium also shows +4 oxidation state because:
(i) it has variable ionisation enthalpy
(ii) it has a tendency to attain noble gas configuration
(iii) it has a tendency to attain f 0 configuration
(iv) it resembles Pb4+
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 statements given in Column I with the oxidation states given in Column II.
| Column I | Column II | |
| (i) | Oxidation state of Mn in MnO2 is | (a) + 2 |
| (ii) | Most stable oxidation state of Mn is | (b) + 3 |
| (iii) | Most stable oxidation state of | (c) + 4 |
| Mn in oxides is | (d) + 5 | |
| (iv) | Characteristic oxidation state of lanthanoids is | (e) + 7 |
On the basis of Lanthanoid contraction, explain the following:
Stability of the complexes of lanthanoids.
On the basis of Lanthanoid contraction, explain the following:
Radii of 4d and 5d block elements.
How would you account for the following:
There is a greater range of oxidation states among the actinoids than among the lanthanides.
The titanium (Z = 22) compound that does not exist is:-
In lanthanoid the last electron enters (n - 2)f subshell where n is equal to ______.
Zr(Z = 40) and Hf(Z = 72) have similar atomic and ionic radii because of ______
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of ______.
The lathanide ion that would show colour is ______.
Which one of the lanthanoids given below is the most stable in divalent form?
Write a note on lanthanoids.
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)
Name an important alloy which contains some of the lanthanoid metals.
Mention alloy uses.
