Acids & Bases

Properties of Acids and Bases Acids react with bases Acids are electrolytes Acids act on some metals to produce H2(g) Acids turn litmus paper RED Acids taste SOUR. Bases react with acids Bases are electrolytes Bases feel slippery Bases turn litmus paper BLUE Bases taste BITTER.

Litmus is: RE LUE ACI ASE D

The pH scale is a number scale for measuring how acidic or basic a solution is. One simple definition of acids is that they are chemical compounds that produce a solution with a pH of less than 7 when they dissolve in water. Bases are compounds that produce a solution of pH of more than 7 when they dissolve in water. If a solution has a pH of 7, it is said to be neutral (neither acidic nor basic). Notice that the “p” in pH is always lower case, and the “H” is always upper case. pH values do not have a unit of measurement written after the number.

IndicatorS An INDICATOR is a weak organic acid or base with different colors for its conjugate acid and base forms. Ex :HIn + H2OIn- + H3O+ yellow red When the indicator is in acid, the excess H3O+ shifts the equilibrium and the solution turns YELLOW. An indicator is in its CONJUGATE ACID form when in HIGHLY ACIDIC solutions: [HIn]>[In-] In basic solutions, the [H3O+] is very low so that the equilibrium shifts to the In- side and the solution turns RED. An indicator is in its CONJUGATE BASE form when in HIGHLY BASIC solutions:[HIn]<[In-] ***Note: HIn is acid form of indicator. In- is the conjugate base of the indicator.

Indicators                                                         A UNIVERSAL INDICATOR is an indicator solution which changes color several times over a range of pH values.

Some Common Acids and Bases that You Should Know Sulphuric Acid: H2S04 Hydrochloric Acid: HCl Nitric Acid: HNO3 Acetic Acid: CH3COOH Sodium Hydroxide: NaOH Potassium Hydroxide: KOH Ammonia: NH3

Some work for you to try!! Workbook Page 84 & 85