Which of the following contains covalent bond ?A CaF2 B CCl4 C MgCl2 D Al2O3

The covalent bond is a type of chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.

Let's analyze the options:

A. CaF2 - Calcium Fluoride: This is an ionic compound. Calcium is a metal and Fluorine is a non-metal. Metal and non-metal compounds are usually ionic.

B. CCl4 - Carbon Tetrachloride: This is a covalent compound. Both Carbon and Chlorine are non-metals and non-metal compounds are usually covalent.

C. MgCl2 - Magnesium Chloride: This is an ionic compound. Magnesium is a metal and Chlorine is a non-metal. Metal and non-metal compounds are usually ionic.

D. Al2O3 - Aluminum Oxide: This is an ionic compound. Aluminum is a metal and Oxygen is a non-metal. Metal and non-metal compounds are usually ionic.

So, the compound that contains a covalent bond is B. CCl4 - Carbon Tetrachloride.