Question

The bond angle in ethylene is:
A) \[180^\circ \]
B) \[120^\circ \]
C) \[109^\circ \]
D) \[90^\circ \]

Answer 1

Hint: Ethylene is a molecule having two numbers of the carbon atom and one double bond. It is written as \[{{\rm{H}}_{\rm{2}}}{\rm{C}} = {\rm{C}}{{\rm{H}}_{\rm{2}}}\] . To find out the bond angle of ethylene, we have first to find out the hybridization of the carbon atoms, so that we can have an idea of how many groups are bonded to the central atom.

Complete Step by Step Answer:
Let's find the hybridization of carbon atoms. The count of groups surrounding the first atom of carbon is 3, so its hybridization is \[s{p^2}\] . Similarly, in the 2nd atom of carbon, the count of groups surrounding the central atom is 3, so its hybridization is \[s{p^2}\]. So, we find that both carbon atoms have the hybridization of \[s{p^2}\]. And, we know, in the case of \[s{p^2}\] hybridised molecules, the bond angle is \[120^\circ \].
Hence, option B is right.

Additional Information: A short trick to check the hybridization of a molecule is, we have to look at the number of surrounding groups around the central atom. The surrounding groups are atoms that form bonds with the central atom and lone pair groups. If the count of groups is two, then the hybridization is sp. If the count of groups is three, the hybridization is \[s{p^2}\]. If the count of groups is four, the hybridization is \[s{p^3}\].

Note: Ethylene is a hydrocarbon, which is present in the form of gas. It is a gas of no colour and flammable in nature. It is used in chemical industries in abundance. Its use in the farming practices such as the ripening of fruits is significant.