Because the bond of highly reactive with oxide is very strong in the comparison of the bond of. carbon with oxide so carbon unable to extract the highly reactive metal with from its oxide

Reasons why highly reactive metals cannot be obtained from their oxides by heating them with carbon:

1. Oxidation and Reduction Reactions:
When a metal oxide is heated with carbon, a redox reaction takes place. The carbon acts as a reducing agent, which means it donates electrons to the metal oxide. This reduction reaction results in the formation of carbon dioxide (CO2) and the metal. However, highly reactive metals have a strong affinity for oxygen, making it difficult for carbon to displace oxygen from their oxides.

2. Stability of Metal Oxides:
Highly reactive metals, such as potassium, sodium, calcium, and magnesium, form stable oxides. These metal oxides have a strong ionic bond between the metal cation and the oxygen anion. The stability of these metal oxides makes it energetically unfavorable for carbon to replace oxygen during the reduction process.

3. Thermodynamic Considerations:
The reduction of metal oxides by carbon involves overcoming the thermodynamic stability of the metal oxide. In the case of highly reactive metals, the thermodynamic stability of their oxides is high, meaning that a large amount of energy is required to break the strong metal-oxygen bonds. The carbon is unable to provide enough energy to overcome this stability, resulting in an ineffective reduction process.

4. Formation of Carbon Monoxide:
In some cases, when metal oxides are heated with carbon, instead of forming the desired metal, carbon monoxide (CO) is produced. This occurs when the metal oxide is not thermodynamically favorable to be reduced by carbon. The formation of carbon monoxide instead of the metal further indicates the inability of carbon to effectively reduce highly reactive metal oxides.

5. Alternative Extraction Methods:
Due to the limitations of carbon reduction, alternative extraction methods are used to obtain highly reactive metals. These methods include electrolysis and the use of more powerful reducing agents. Electrolysis involves passing an electric current through a molten metal compound, while more powerful reducing agents, such as aluminum or sodium, are used to directly displace the metal from its oxide.

In conclusion, highly reactive metals cannot be obtained from their oxides by heating them with carbon due to the strong affinity of these metals for oxygen, the stability of their oxides, thermodynamic considerations, the formation of carbon monoxide, and the availability of alternative extraction methods.