The solubility of alkali metal salts in water is due to the fact that the cations get hydrated by water molecules. What is the relative degree of hydration?

Question

The solubility of alkali metal salts in water is due to the fact that the cations get hydrated by water molecules. What is the relative degree of hydration? (A) Cs(a q)+>Rb(a q)+>K(a q)+>Na(a q)+>Li(a q)+ (B) Li(a q)+>Na(a q)+>K(a q)+>Rb(a q)+>Cs(a q)+ (C) Na(a q)+>K(a q)+>Rb(a q)+>Cs(a q)+>Li(a q)+ (D) Cs(a q)+>Na(a q)+>Li(a q)+>K(a q)+>Rb(a q)+

Tardigrade Admin · Accepted Answer

As hydration energy propto charge on cation propto (1/ textsize of cation) As on moving down size of ion increases so degree of hydration decreases hence the correct order is Li(a q)+>Na(a q)+>K(a q)+>Rb(a q)+>Cs(a q)+

Q. The solubility of alkali metal salts in water is due to the fact that the cations get hydrated by water molecules. What is the relative degree of hydration?

$C s_{(a q)}^{+} > R b_{(a q)}^{+} > K_{(a q)}^{+} > N a_{(a q)}^{+} > L i_{(a q)}^{+}$

$L i_{(a q)}^{+} > N a_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+} > C s_{(a q)}^{+}$

$N a_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+} > C s_{(a q)}^{+} > L i_{(a q)}^{+}$

$C s_{(a q)}^{+} > N a_{(a q)}^{+} > L i_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+}$

As hydration energy $\propto$ charge on cation $\propto \frac{1}{size of cation}$
As on moving down size of ion increases so degree of hydration decreases hence the correct order is
$L i_{(a q)}^{+} > N a_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+} > C s_{(a q)}^{+}$

Q. The solubility of alkali metal salts in water is due to the fact that the cations get hydrated by water molecules. What is the relative degree of hydration?

Cs(aq)+​>Rb(aq)+​>K(aq)+​>Na(aq)+​>Li(aq)+​

Li(aq)+​>Na(aq)+​>K(aq)+​>Rb(aq)+​>Cs(aq)+​

Na(aq)+​>K(aq)+​>Rb(aq)+​>Cs(aq)+​>Li(aq)+​

Cs(aq)+​>Na(aq)+​>Li(aq)+​>K(aq)+​>Rb(aq)+​

As hydration energy ∝ charge on cation ∝size of cation1​ As on moving down size of ion increases so degree of hydration decreases hence the correct order is Li(aq)+​>Na(aq)+​>K(aq)+​>Rb(aq)+​>Cs(aq)+​

$C s_{(a q)}^{+} > R b_{(a q)}^{+} > K_{(a q)}^{+} > N a_{(a q)}^{+} > L i_{(a q)}^{+}$

$L i_{(a q)}^{+} > N a_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+} > C s_{(a q)}^{+}$

$N a_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+} > C s_{(a q)}^{+} > L i_{(a q)}^{+}$

$C s_{(a q)}^{+} > N a_{(a q)}^{+} > L i_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+}$

As hydration energy $\propto$ charge on cation $\propto \frac{1}{size of cation}$
As on moving down size of ion increases so degree of hydration decreases hence the correct order is
$L i_{(a q)}^{+} > N a_{(a q)}^{+} > K_{(a q)}^{+} > R b_{(a q)}^{+} > C s_{(a q)}^{+}$