Table of Contents
- 1 What is the effect of lanthanide contraction on extraction of lanthanides by ion exchange method?
- 2 Which out of Lu OH 3 is more basic and why?
- 3 Why separation of lanthanides is difficult discuss the ion exchange method for the separation of lanthanides?
- 4 Why there is problem in separation of lanthanides from each other?
- 5 Which of the following is most basic Al OH 3?
- 6 What happens due to lanthanide contraction?
What is the effect of lanthanide contraction on extraction of lanthanides by ion exchange method?
Due to lanthanide contraction the decrease in size of Ln+3 ions from La+3 to Lu+3 increases the covalent character ( i.e. decreases the ionic character ) between Ln+3 and OH- ions in Ln(III) hydroxides.
Which out of Lu OH 3 is more basic and why?
Due to lanthanide contraction, the size of Lu3+ is decreased and therefore Lu(OH)3 shows more covalent character (Small cation, more is covalent character – Fajan’s rule). Thus La(OH)3 is more ionic and thus more basic.
Is La OH 3 or Lu OH 3 more basic?
La(OH)3 is most basic and Lu(OH)3 is least basic. As the size of lanthanide ions decreses from La3+ to Lu3+ , the covalent character of the hydroxides increases and hence the basic strength decreases.
How the lanthanide contraction affects the basicity of ions?
As the atomic size increases, the basicity of oxides and hydroxides decreases. Due to lanthanide contraction, there is a reduce in the size of lanthanide cations that increases the polarizing control of cations.
Why separation of lanthanides is difficult discuss the ion exchange method for the separation of lanthanides?
Because of Lanthanide contraction the lanthanides from 1 to 14 differ in their ionic size ie., decrease downwards. Many properties like solubility,difference in solubility, complex formation, stability of complexes etc making use of these properties different lanthanide ions can he separated.
Why there is problem in separation of lanthanides from each other?
Lanthanides are difficult to separate from each other because of similarities in their physical and chemical properties. The extractant liquid contains arms, called ligands, that grab the lanthanide. For an ideal ligand, the decrease in ionic radius would result in steadily increasing extraction across the series.
Which of the following statements is not correct a la OH 3 is less basic than Lu OH 3?
Correct option (a) La(OH)3 is less basic than Lu(OH) 3. Explanation : La(OH)3 is more basic than Lu(OH)3. In lanthanides the basic character of hydroxides decreases as the ionic radius decreases.
Which of the following is strongest base La OH 3 Pr OH 3 CE OH 3 Lu OH 3?
Answer: Lu(OH)3 is the strongest base as the basic ch.
Which of the following is most basic Al OH 3?
La(OH)3 is the most basic as it has the largest atomic size. Al(OH)3 is amphoteric in nature.
What happens due to lanthanide contraction?
Since lanthanide elements are having ‘f’ subshell electrons these electrons have the lowest shielding effect. Thus, the atomic and ionic decreases. This phenomenon is known as lanthanoid contraction. Due to lanthanide contraction in the lanthanide series of elements there is a decrease in both atomic and ionic radii.
What is the effect of lanthanide contraction on basic strength of lanthanide hydroxide?
Effects of lanthanoid contraction:- (a) Effects on the basic strength of hydroxides: As the size of the lanthanoid ions decreases from La3+ to Lu3+, the covalent character of the hydroxides increases. Thus, the basic strength decreases.
Why separation of lanthanides is difficult?