Question
Discuss chemical properties of lanthanoids.
✓
Answer
→ In their chemical behaviour, in general, the earlier members of the series are quite reactive similar to calcium but, with increasing atomic number, they behave more like aluminium.
→ The value of $E ^0$ of half reaction
$
\operatorname{Ln}_{( aq )}^{3+}+3 e ^{-} \longrightarrow Ln ( s ) \text { range from }-2.21
$
to 2.4 V except for Eu that has -2.0 V .
→ Lanthanoids heated with carbon forms carbides Ln3C, Ln2C3 and LnC2
→ Lanthanoids form trihalides LnX3 with halogen and liberates hydrogen gas when treated with dilute acids.
→These metals combine with oxygen to form oxides of type Ln2O3
→ Oxides are basic in nature and when dissloved in water they form hydroxide Ln(OH)3.
→ The value of $E ^0$ of half reaction
$
\operatorname{Ln}_{( aq )}^{3+}+3 e ^{-} \longrightarrow Ln ( s ) \text { range from }-2.21
$
to 2.4 V except for Eu that has -2.0 V .
→ Lanthanoids heated with carbon forms carbides Ln3C, Ln2C3 and LnC2
→ Lanthanoids form trihalides LnX3 with halogen and liberates hydrogen gas when treated with dilute acids.
→These metals combine with oxygen to form oxides of type Ln2O3
→ Oxides are basic in nature and when dissloved in water they form hydroxide Ln(OH)3.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The following data were obtained during the first order thermal decomposition of N2O5(g) at a constant volume:
2N2O5(g) → 2N2O4(g) + O2(g)
Calculate the rate constant.
2N2O5(g) → 2N2O4(g) + O2(g)
| S. No. | Time/s | Total pressure/atm |
| 1. | 0 | 0.5 |
| 2. | 100 | 0.512 |
Compare the chemistry of actinoids with that of the lanthanoids with special reference to:
Chemical reactivity
Chemical reactivity
Give reasons for the following:
- Acetylation of aniline reduces its activation effect.
- CH3NH2 is more basic than C6H5NH2.
- Although -NH2 is o/p directing group, yet aniline on nitration gives a significant amount of m-nitroaniline.
Giving a suitable example for each, explain the following:
- Crystal field splitting.
- Linkage isomerism.
- Ambidentate ligand.
A current of 1.50A was passed through an electrolytic cell containing AgNO3 solution with inert electrodes. The weight of Ag deposited was 1.50g. How long did the current flow?
How would you account for the following:
- The transition elements have high enthalpies of atomisation.
- The transition metals and their compounds are found to be good catalysts in many processes.
(i) What is the role of activated charcoal in gas mask?
(ii) A colloidal sol is prepared by the given method in figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the sol represented?
(iii) How does chemisorption vary with temperature ?
(ii) A colloidal sol is prepared by the given method in figure. What is the charge on hydrated ferric oxide colloidal particles formed in the test tube? How is the sol represented?
(iii) How does chemisorption vary with temperature ?
What is meant by hydroboration oxidation reaction? Illustrate with an example.
Write about oxidation states of transition series ?
For the reaction :
2A + B → A2B
the rate $= k [ A ][ B ]^2$ with $k =2.0 \times 10^{-6} mol^{-2} L^2 s^{-1}$.Calculate the initial rate of the reaction when [A] = 0.1 mol L-1. [B] = 0.2 mol L-1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L-1.
→2A + B → A2B
the rate $= k [ A ][ B ]^2$ with $k =2.0 \times 10^{-6} mol^{-2} L^2 s^{-1}$.Calculate the initial rate of the reaction when [A] = 0.1 mol L-1. [B] = 0.2 mol L-1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L-1.