# FAQ overflow

#### QUESTION

If I get a pure solution of an acid chloride and place a pH meter into the liquid, will I get a reading of pH 7?

When I add water to it, I know $HCl$ gas will form but will this gas dissolve in water to give an acidic solution.

My main confusion is that we call ethanoyl chloride as an "acid" chloride... but is its pure solution acidic?

An acid chloride is a covalent molecule. It has no pH. If you put a pH electrode into a reactive acid chloride you will dehydrate and acylate its hydrated glass surface ($\ce{#Si-OH}$) and damage its future response when properly used. pH electrodes are stored sitting in buffer or saline solution.
An acid chloride is an oxo-acid whose acidic $\ce{-OH}$ has been replaced with $\ce{-Cl}$. Hydrolysis restores the oxo-acid, displacement makes derivatives. Hdrochloric acid is NOT an acid chloride.