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प्रश्न
What is the action of the following on lanthanoids?
a. water
b. Sulphur, heat
c. nitrogen, heat
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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).
\[\ce{2Ln + 3S ->[\Delta] Ln2S3}\] - Action of nitrogen on lanthanoids: Reaction of nitrogen with lanthanoide gives lanthanide nitride (LnN).
\[\ce{2Ln + N2 ->[\Delta] 2LnN}\]
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संबंधित प्रश्न
What are chemical twins? Write ‘two’ examples.
What are lanthanoids?
Which among the following pairs of elements is 'not' an example of chemical twins?
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.
What are the different oxidation states exhibited by the lanthanoids?
Compare the chemistry of actinoids with that of lanthanoids with special reference to electronic configuration.
Compare the chemistry of actinoids with that of the lanthanoids with special reference to atomic and ionic sizes.
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.
Account for the following:
Zn, Cd and Hg are soft metals.
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 |
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:
Stability of the complexes of lanthanoids.
Which of the following pairs has the same ionic size?
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 ______.
The lathanide ion that would show colour is ______.
State a reason for the following:
La(OH)3 is more basic than Lu(OH)3.
Trivalent Lanthanoid ions such as La3+ (Z = 57) and Lu3+ (Z = 71) do not show any colour in their solution. Give a reason.
Name an important alloy which contains some of the lanthanoid metals.
The pair of lanthanoid ions which are diamagnetic is:
