Hydrogen bonding is an important intermolecular force in which of the following compounds: hf, ch3ch3, ch3oh, and h2s?

HF because hydrogen must be bonded to either oxygen, nitrogen, or fluorine, the 3 most electronegative elements on the periodic table.

It is a ok  i know i have a brain functioning well.                                                                                                                                                           

The question is incomplete. complete question is attached belowanswer: correct answer is option b  i.e.  solid particles  reason: filter paper has small pores, through which smaller particles can pass through. however, solid particles  have relatively larger size. hence, they are least likely to pass through.