In everyday life we deal with many compounds that chemist classify as acids and bases. For example, organic juice and lemon juice contain citric acid (an acid) and lye (material to make soap) which contains sodium hydroxide (a base). We can use our taste buds to determine that these examples are acidic or basic. An acids tend to have a sour taste, such as lemon juice, while bases have a bitter taste and slippery to feel, such as soap. Tasting a chemicals to determine if they were acid or basic wouldn’t be a great idea therefore we measure how acidic or basic something is by its pH. The pH the pH scale goes from 0 to 14 and acids are found between 0 to 7 and bases are from 7 to 14.  The middle point of the pH scale is 7 and distilled water is exactly 7.

When strong acids and strong bases are added together a neutralization reaction occurs forming a salt and water. For example the acid found in our stomachs is extremely acidic (see scale below) while milk of magnesia, commonly found in antacids. Think about the last time you had really bad heartburn, causes by stomach acid at a very low pH, in order to relieve the heartburn you took a Tums or another antacid. The antacid is basic and once it reaches the acid it increases the pH of the acid through a neutralization process.

In this experiment we will be mixing different concentrations of a strong acid (HCl) and a strong base (NaOH) to form neutralization reactions. The various concentrations of strong acid and strong base will combined with one another to form a salt and water. We will measure the pH of the acid, base and neutralization solutions to show that pH is affected by concentration and that concentration should not affect the pH of a neutralized solution. Finally all water will be removed from the neutralized solution and the mass of salt will be determined. This experiment will also introduce you to the use of pH meters as well as reinforce stoichiometry, molarity, percent yield and experimental error