Question

Which among the given compounds is/are held together by a covalent bond?

• A. Sodium fluoride
• B. Hydrogen chloride
• C. Sodium chloride
• D. Magnesium oxide

Answer 1

The correct option is B

Hydrogen chloride

A chemical bond formed as a result of the sharing of electrons between the combining atoms is called a covalent bond. In the given options :

• Hydrogen chloride is a covalent compound. In hydrogen chloride, hydrogen has one valence electron and chlorine has seven valence electrons in its outermost shell. Hence hydrogen and chlorine share one pair of electrons forming a covalent bond.
  
• Sodium fluoride is an ionic compound. In sodium fluoride, sodium has one valence electron and fluorine has seven valence electrons in its outermost shell. Hence sodium donates one electron to fluorine in order to attain stability. As a result, an ionic bond is formed.
  
• Sodium chloride is an ionic compound. In sodium chloride, sodium has one valence electron and chlorine has seven valence electrons in its outermost shell. Hence sodium donates one electron to chlorine, forming an ionic bond.
  
• Magnesium oxide is an ionic compound. In magnesium oxide, magnesium has two electrons and oxygen has six electrons in its outermost shell. As a result, magnesium donates two electrons to oxygen, forming an ionic bond.