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Ethers have a tetrahedral geometry i.e. oxygen is sp
3
hybridized. The C−O−C bond angle is 110
o
. Because of the greater electronegativity of O than C, the C−O bonds are slightly polar & are inclined to each other at an angle of 110
o
, resulting in a net dipole moment. This bond angle greater than that of tetrahedral bond angle of 109
o
28
′
. This is due to the fact that internal repulsion by the hydrocarbon part is greater than the external repulsion of the lone pair of oxygen.
Answer: To answer your question of what is true of a lewis base, it is true that a lewis base donates electron pairs.
Explanation: A Lewis base is any substance, such as the OH- ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an electron-pair donor.