Studying the pH of Strong Acid, Weak Acid, Salt, and Buffer Solutions

1676 WordsNov 4, 20147 Pages
Studying the pH of Strong Acid, Weak Acid, Salt, and Buffer Solutions The purpose of the current experiment was to determine the pH of various hydrochloric acid and acetic acid solutions, to determine the pH of various salt solutions, to prepare a buffer solution, and determine the effects of adding a strong acid and strong base to the buffer solution versus adding a strong acid and strong base to water. The measured pHs for the hydrochloric acid solutions were 1.6, 2.2, 2.9, and 3.8. The measured pHs for the acetic acid solutions were 2.9, 3.9, 4.2, and 4.4. The pHs measured for the salts were 4.3 for sodium chloride, 7.3 for sodium acetate, 8.9 for sodium bicarbonate, 10.8 for sodium carbonate, 7.9 for ammonium chloride, and 6.9 for…show more content…
When an ionic solution dissolves in water, it dissociates into a cation and anion. The ions are surrounded by water molecules and under this circumstance some salts will react with the water molecules through a process called hydrolsis1. The anions of strong acids and the cations of strong bases do not hydrolyze. Therefore, the resulting pH is 7.01. Depending on whether a weak acid or base was added to the water, salts of different pHs can be formed. Basic salts are a product of the reaction between a strong base and a weak acid. Acidic salts are the product of the reaction between a strong acid and weak base1. There are also neutral salts which are the product of the reaction between a strong acid and strong base and salts that can be acidic, basic, or neutral because of the reaction between a weak acid and a weak base1. 3.0x10-8= QUOTE Solutions that undergo a minimal pH change when an acid or base is added are called buffer solutions1. A buffer solution can be prepared by mixing a weak acid and a salt containing the anion of that acid, like HClO and NaClO. A buffer solution can also be prepared by mixing a weak base with a salt containing the cation of the base. The pH of a buffer solution can be calculated by using the Ka expression and substituting the buffer solution conditions (concentration of solutions in buffer)1. pH = -log (3.0x10-8) = 7.52 3.0x10-8= [H3O+] [ClO-1]/ [HClO] QUOTE [H3O+]

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