Sodium and potassium react with water much more vigorously than lithiu...
When sodium and potassium react with water the heat evolved cause them to melt,giving larger surface for the above reaction.
Melting point order Li>Na>K the reactivity order is just the opposite. Hope this answer helps.
Sodium and potassium react with water much more vigorously than lithiu...
Explanation:
When sodium, potassium, and lithium react with water, they form metal hydroxides and release hydrogen gas. However, sodium and potassium react much more vigorously than lithium. This difference in reactivity can be explained by considering the properties of these alkali metals.
Melting Point:
- Sodium and potassium have lower melting points than lithium.
- Sodium has a melting point of 97.8°C, potassium has a melting point of 63.7°C, while lithium has a melting point of 180.5°C.
- The lower melting points of sodium and potassium indicate that they are more easily molten than lithium.
- This allows them to react more readily with water, as the heat generated in the reaction can easily melt them.
Hydration Energy:
- Hydration energy refers to the energy released when a substance is hydrated or dissolved in water.
- Sodium and potassium have lower hydration energies than lithium.
- This means that sodium and potassium ions are more highly hydrated than lithium ions when dissolved in water.
- The high degree of hydration makes it easier for sodium and potassium ions to react with water, as the water molecules can easily surround and solvate the ions, facilitating the reaction.
Reactivity with Water:
- The reactivity of alkali metals with water is determined by the ease with which they can lose electrons to form positive ions.
- Sodium and potassium have lower ionization energies than lithium, meaning they can more readily lose electrons and form positive ions.
- The lower ionization energies of sodium and potassium contribute to their higher reactivity with water compared to lithium.
- Additionally, the lower melting points and higher hydration energies of sodium and potassium further enhance their reactivity with water.
Conclusion:
In conclusion, sodium and potassium react more vigorously with water than lithium due to their lower melting points, lower hydration energies, and lower ionization energies. These factors make sodium and potassium more easily molten, highly hydrated, and more prone to losing electrons, allowing them to react more readily with water.
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