Question

The $C - O - C$ bond angle in diethyl ether is:
A. $109^\circ 28'$
B. $110^\circ$
C. $120^\circ$
D. $180^\circ$

Answer 1

The chemical formula for diethyl ether is ${C_2}{H_5}O{C_2}{H_5}$ . It is the most common ether known historically. Ether has tetrahedral geometry and Oxygen is $s{p^3}$ hybridized. Since Oxygen atom is more electronegative than Carbon atom, the $C - O$ bonds are slightly polar & are inclined to each other.

Complete answer:
The geometry of Ethers is a tetrahedral i.e., oxygen is $s{p^3}$ hybridized. The $C - O - C$ bond angle is $110^\circ$ . Due to the greater electronegativity of Oxygen atom than Carbon atom, the $C - O$ bonds are slightly polar and are inclined to each other at an angle of $110^\circ$ which results in a net dipole moment. This bond angle is greater than that of the tetrahedral bond angle of $109^\circ 28'$. This is because the internal repulsion by the hydrocarbon part is greater than the external repulsion of the lone pair of oxygen (O).
Also, the $C - O - C$ bond angle is not $180^\circ$ as the dipole moments of the two $C - O$ bonds do not cancel each other, which consequently, ether possess a small net dipole

Therefore, the correct answer is option (B).

Note: Diethyl ether is also commonly known as ether. It is a volatile, flammable and colourless liquid with a distinctive odour. It belongs to the large group of organic compounds called ethers. It is also known by the name ethyl ether. The density of diethyl ether is $713\dfrac{{kg}}{{{m^3}}}$ . Its molecular mass is $74.12\dfrac{g}{{mol}}$ . It is used as a common laboratory solvent, as an excellent solvent for alkaloids, dyes, fats, oils, resins and waxes and also used in the recovery of acetic acid from aqueous solutions in cellulose acetate and plastic industry.