Yes, sodium can displace calcium.
Based on the activity series of metals, sodium is more reactive than calcium. This means that sodium has a stronger tendency to lose electrons and form positive ions compared to calcium.
Understanding Metal Displacement
Metal displacement reactions occur when a more reactive metal displaces a less reactive metal from its compound (like a salt solution or molten salt). The reactivity series is a crucial tool for predicting whether such a reaction will happen.
The Reactivity Series
The reactivity series ranks metals from the most reactive to the least reactive. The order reflects the ease with which metals lose electrons and undergo oxidation.
According to the provided reference: "The reactivity series is a list of metals arranged in the order of their decreasing activities. Sodium is the second metal of activity series so it can displace calcium, magnesium and iron because all of them come after sodium in activity series."
This clearly positions sodium above calcium in the series regarding reactivity.
Here's a simplified snippet showing the relevant portion:
| Metal | Reactivity |
|---|---|
| Potassium | Highest |
| Sodium | |
| Calcium | |
| Magnesium | |
| Aluminium | |
| Zinc | |
| Iron | |
| Lead | |
| Hydrogen* | |
| Copper | |
| Silver | |
| Gold | Lowest |
*Hydrogen is included for reference with acids and water reactions.
Why Sodium Can Displace Calcium
Since sodium is higher in the reactivity series than calcium, it is more reactive. In suitable conditions (like molten salts where ions are mobile, as both are highly reactive metals and reaction in water would be complex due to their reactions with water), sodium can reduce calcium ions back to calcium metal while sodium itself gets oxidized to sodium ions.
For example, consider a theoretical reaction in molten salts:
2Na(l) + CaCl₂(l) → 2NaCl(l) + Ca(l)
Here, liquid sodium reacts with molten calcium chloride. The more reactive sodium displaces calcium from its compound, forming molten sodium chloride and elemental calcium.
This concept is a fundamental principle in understanding the chemical behavior of metals and predicting the outcome of displacement reactions. The position of metals in the reactivity series directly indicates their ability to displace other metals below them.
