Acids & Bases

Acid Properties taste sour (Don’t taste anything in lab!) show a definite color change when mixed with an indicator turn litmus from blue to red phenolphthalein is colorless in acids universal indicator is red in acids

Acid Properties react with metals to produce H 2 & metal compound produces H + in water The H +, or proton, is quickly attracted to the polar water molecule to form a hydronium ion (H ). weak acids - produce few H + in water strong acids - produce many H + in water pH from 0 to < 7

Acid Concentration Concentration of an acid is independent of it being strong or weak. There are concentrated weak acids and dilute weak acids. There are concentrated strong acids and dilute strong acids.

Acid Examples aspirin (acetysalicylic acid) vitamin C (ascorbic acid) fruit (citric acid) milk (lactic acid) vinegar (acetic acid) pop (carbonic acid) batteries (sulfuric acid) stomach (hydrochloric acid)

Acids are neutralized by a simple double replacement reaction. H 2 SO 4 + NaOH  Na 2 SO 4 + HOH

Base Properties taste bitter slippery to the touch emulsify, or dissolve, fats & oils show a definite color change when mixed with an indicator –turn litmus from red to blue –phenolphthalein is pink in bases –universal indicator is blue in bases

Base Properties produce OH -1 in water weak bases - produce few OH -1 in water strong bases - produce many OH -1 in water pH from 14 through >7

Base Concentration Concentration of a base is independent of it being strong or weak. There are concentrated weak bases and dilute weak bases. There are concentrated strong bases and dilute strong bases.

Base Example lye soap milk of magnesia ammonia deodorants antacid

Acid Formulas Usually begin with the H + ion. H 2 SO 4 H 3 PO 4 Sometimes end in –COOH Organic acids such as acetic acid (CH 3 COOH)

Base Formulas Usually end with the OH -1 ion. NaOH Mg(OH) 2 NH 4 OH Not all formulas ending in OH are bases The alcohol group ends in OH but does not yield the OH -1 when dissolved in water (i.e. CH 3 OH)