I understand the following definition of a hydrogen bond from Merriam Webster:
an electrostatic attraction between a hydrogen atom in one polar molecule (as of water) and a small electronegative atom (as of oxygen, nitrogen, or fluorine) in usually another molecule of the same or a different polar substance
However, I wasn't sure if this applied to F, N, or O atoms that were not covalently bonded to H in the first place. A question regarding hydrogen-bonding came up on an exam for which the marks scheme read that both element X (with an O-H bond) and element Y (with an O in an ether group). However my teacher doesn't not agree with the marks scheme and, "[believes that the marks-scheme is] incorrect because Y doesn't contain O-H bonds so the O will not carry a large enough δ- to create hydrogen bonds with water."
Is she correct, or is the marks scheme?
Note: I thought the same as my teacher up until I saw the MS.