The notation [H+] refers to the Naim 00:09 Small Molecules and the Chemistry of Life The notation [H+] refers to the a. number of H+ ions present in a solution. b. number of protons in an H+ ion. c. charge of an H+ ion. d. concentration of H+ ions in moles per liter. e. chemical reactivity of H+ ions. Answer: D Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+