Which one among the following oxides has the highest melting point ?

Join Our Telegram Channel

Na₂O

MgO

Fe₂O₃

CuO

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC NDA-1 – 2024

Download PDF Attempt Online

Among the given options, Magnesium oxide (MgO) has the highest melting point.

Oxides of highly electropositive metals (like those in Group 1 and 2) and transition metals are generally ionic compounds with high melting points due to strong electrostatic forces in the crystal lattice. MgO is a Group 2 metal oxide with high lattice energy primarily due to the +2 and -2 charges of Mg²⁺ and O²⁻ ions and their relatively small ionic radii, resulting in a very high melting point (~2852 °C).

Comparing the options: Na₂O (~1132 °C), MgO (~2852 °C), Fe₂O₃ (~1565 °C, decomposes), CuO (~1326 °C, decomposes). MgO’s melting point is significantly higher than the others listed, making it a refractory material.

More similar MCQ questions for Exam preparation:-