Acids and Bases

HCl H2SO4 HNO3 HCH3COO NaOH Ba(OH)2 KOH Ma(OH)2

Acids are ionic compounds that start with hydrogen (H+) HCl (hydrochloric acid) H2SO4 (sulphuric acid) Bases are ionic compounds that end with hydroxide (OH-) NaOH (sodium hydroxide) KOH (potassium hydroxide)

Common Acids and Bases Common Acids Common Bases

pH Scale You can find out if a compound is an acid or a base by measuring its pH. pH stands for “power of hydrogen” and refers to how much H+ ions is present in a given solution. The more H+, the more acidic it is The less H+, the less basic it is pH scale is a numeric scale (0-14) that tells you how acidic or basic a solution is.

pH Scale

Acid-Base Indicators There are several methods to test the pH of a solution. An acid-base indicator is a substance that changes colour in presence of an acid or a base. Acid Base (or neutral) universal indicator paper litmus paper phenolphthalein

cabbage juice indicator Acid Neutral Base bromothymol blue indicator

Properties of Acids and Bases pH < 7 Tastes sour Corrosive Turn blue litmus paper red Electrolytes (conduct electricity) HCl (aq)  H+ (aq) + Cl- (aq) Corrode metals React with metals to produce a compound and H2 (g). Mg (s) + 2HCl (aq)  MgCl2 (aq) + H2 (g) React with carbonates to produce CO2. 2HCl (aq) + Na2CO3 (aq)  2NaCl (aq) + CO2 (aq) + H2O (l) pH > 7 Tastes bitter Corrosive Slippery feel (eg. Soap) Turn red litmus paper blue Electrolytes (conduct electricity) NaOH (aq)  Na+ (aq) + OH- (aq) Do not corrode metals Do not react with metals

6. Neutralization Key Points: Special type of double displacement reaction between an ACID and a BASE to produce an IONIC SALT and WATER. If you spill a base, you can neutralize it with an acid and vice versa.

Naming & Writing Formulas Acids Write prefix hydro (if you have an element as a metal) and the element name but include the suffix ic If it is a polyatomic ion that follows the H, simply write the polyatomic name but include the suffix ic. Follow up with acid afterwards Eg. HF & H3PO4 Bases Write the element name of the metal or name of polyatomic ion Follow up with hydroxide afterwards Eg. Ca(OH)2 & NH4OH