Question

Which of the following statements concerning double covalent bonds is correct?

1. They are found only in molecules that contain S or O.
2. They are found only in molecules that contain a coordinate covalent bond.
3. They occur only between atoms containing 4 valence electrons.
4. They always involve the sharing of 2 electron pairs.

Answer 1

Answer:-

As we know that there are many atoms which can form double covalent bonds such as C , P , S , O , N etc. therefore statement (a.) i.e They are found only in molecules that contain S or O which is incorrect.

The  statement (b.) i.e They (double covalent bonds) are found only in molecules that contain a coordinate covalent bond is incorrect because there are several molecules are known where no coordinate covalent bond is present e.g. C₂H₄ , H₂SO₄ , H₃PO₄ , CO₂etc.

The  statement (c.) i.e They (double covalent bonds) occur only between atoms containing 4 valence electrons is incorrect because there are several atoms which contained more than 4 valence electrons and they form double covalent bonds. e.g. O- atom and S- atoms have 6 valence electrons, which can form can form double covalent bonds.

The  statement (d.) i.e They (double covalent bonds) always involve the sharing of 2 electron pairs is correct option because when double covalent bonds are formed between two atoms, there are sharing 2 electron pairs, 2 electrons from one atom and 2 electrons from other atom.