1
Acids and Bases
2
Acids• React with certain metals to produce
hydrogen gas.• React with bicarbonates to produce
carbon dioxide gas
• Have a bitter taste• Feel slippery. • Many soaps contain bases.
Bases
3
Properties of Acids Produce H+ ions in water Taste sour
Corrode metals
Good Electrolytes
Ions used to transmit signals throughout the body
React with bases to form a salt and waterwater
pH is less than 7
Turns blue litmus paper to red “Blue to Red A-CID”
Some Common Acids
HCHC22HH33OO22 acetic acidacetic acid in vinegarin vinegar
HClHCl hydrochloric acidhydrochloric acid stomach acidstomach acid
HH33CC66HH55OO77 citric acidcitric acid fruitsfruits
HH22COCO22 carbonic acidcarbonic acid soft drinkssoft drinks
H3H322POPO44phosphoric acidphosphoric acid soft drinkssoft drinks
5
Properties of Bases Generally produce OHGenerally produce OH-- ions in water ions in water
Taste bitter, chalkyTaste bitter, chalky
Are electrolytesAre electrolytes
Feel soapy, slipperyFeel soapy, slippery
React with acids to form salts and React with acids to form salts and waterwater
pH greater than 7pH greater than 7
Turns red litmus paper to blueTurns red litmus paper to blue “ “BBasicasic BBluelue””
Some Common Bases
NaOHNaOH sodium hydroxidesodium hydroxide lyelye
KOHKOH potassium hydroxidepotassium hydroxide liquid soapliquid soap
Ba(OH)Ba(OH)22 barium hydroxidebarium hydroxide stabilizer for plasticsstabilizer for plastics
Mg(OH)Mg(OH)22 magnesium hydroxidemagnesium hydroxide “MOM” Milk of magnesia“MOM” Milk of magnesia
Al(OH)Al(OH)33 aluminum hydroxidealuminum hydroxide Maalox (antacid)Maalox (antacid)
The pH scale is a way of expressing the strength of acids and bases. Less than 7 = acid
7 = neutralGreater than 7 = base
The pH values of several common substances are shown at the right.- Many common foods are weak acids- Some medicines and many household cleaners are bases.
pH testing There are several ways to test pH
Blue litmus paper (red = acid)Red litmus paper (blue = basic)pH paper (multi-colored)
• **what we’ll usepH meter (7 is neutral, <7 acid, >7 base)Universal indicator (multi-colored)Indicators like phenolphthaleinNatural indicators like red cabbage,
radishes
pH indicators Indicators are dyes that can be
added that will change color in the presence of an acid or base.
Some indicators only work in a specific range of pH
Once the drops are added, the sample is ruined
Some dyes are natural, like radish skin or red cabbage
Top Related