Acids and Bases- Chemtutor.com By the 1884 definition of Svante Arrhenius (Sweden), an acid is a material that can release a proton or hydrogen ion (H+). Hydrogen chloride in water solution ionizes and becomes hydrogen ions and chloride ions. If that is the case, a base, or alkali, is a material that can donate a hydroxide ion (OH-). Sodium hydroxide in water solution becomes sodium ions and hydroxide ions. We can consider the same idea in the Lowry - Brønsted fashion. Chemists or chemistry texts often use the hydrogen ion, H+ to show a hydrogen ion released into water solution. Back to the beginning of Acids and Bases. For the properties of acids and bases we will use the Arrhenius definitions. Acids release a hydrogen ion into water (aqueous) solution. Acids neutralize bases in a neutralization reaction. Acids corrode active metals. Acids turn blue litmus to red. Acids taste sour. Bases release a hydroxide ion into water solution. Bases neutralize acids in a neutralization reaction. Bases denature protein.
The pH of strong acids and strong bases- Chemteam The pH of strong acids and strong bases Go back to the Acid Base Menu I. Strong Acids The key point is that strong means 100% ionized. HA(s) ---> H+(aq) + A¯ 100% of the HA molecules dissociate in solution. The [H+] of a strong acid is equal to the concentration of the acid. After all, ALL of the acid dissociates. So, here is a typical problem: Calculate the pH of a 0.100 M solution of HCl. In essence, this becomes calculate the pH when the [H+] equals 0.100 M. pH = - log (0.100) = 1.000 It seems pretty easy and it is. Here's another problem: Calculate the pH of a 1.00 M solution of HBr. The solution is: pH = - log (1.00) = 0.00 Yes, that's right, a pH of zero. You might want to watch out. II. Strong bases is pretty much the same as strong acids EXCEPT you'll be calculating a pOH first, then going to the pH. So, the key point is that strong means 100% ionized. BOH(s) ---> B+(aq) + OH¯ 100% of the BOH molecules dissociate in solution. After all, ALL of the base dissociates. Here's another:
QUIZ YOURSELF- pH, pOH, [H+] and [OH-] calculations In aqueous solutions, [H+][OH-] is equal to: 7 M 1 x 10-7 M 1 x 10-14 M 1 x 1014 MWhat is the [OH-] of a solution whose [H+] = 0.001M 1 x 10-11 M 1 x 1011 M 1 x 10-3 M 1 x 103 MThe pH of a 0.0001-M solution of NaOH is: 10 -4 4 11The pH of a softdrink is determined to be 4.0. What is the [OH-] of the drink? 1.0 x 10-4 M 4 M 10 M 1.0 x 10-10 MThe pH of a solution is 3.0. What is the [OH-]? 1 x 10-3 M 11 M 1 x 10-11 M 3 MWhat is the [OH-] of a solution whose pOH = 2.86 ? 7.24 x 10-12 M 724 M 1.38 x 10-3 M 3.50 x 10-15 MWhat is the pOH of a solution whose [OH-] is 9.31 x 10-2 M?