Question 17 (4 marks) (a) Draw the Lewis electron dot structure for the compound, hydrogen fluoride, HF. (1 mark) H F (b) Hydrogen fluoride reacts with water according to the following equationâ¦ HF (l) + H 2 O (l) â H 3 O +(aq) + F â(aq) At room temperature pure hydrogen fluoride exists as a liquid.his shows that water is made up of more than one type of atom. (1 mark) âº The two substances obtained were in definite ratio of 2:1 as shown by the 2:1 ratio of the gas volumes. (1 mark) (ii) State another observation that shows that electrolysis is a chemical change.
Definition of columnist for English Language Learners. : a person who writes a newspaper or magazine column.
1. 1  a critical article or report, as in a periodical, on a book, play, recital, or the like; critique; evaluation. 2  the process of going over a subject again in study or recitation in order to fix it in the memory or summarize the facts. 3  an exercise designed or intended for study of this kind.