1 The Chemistry of Acids and Bases

2 Acid and Bases

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5 Properties of Acids þ most produce H + (as H 3 O + ) ions in water (a hydrogen ion attached to a water molecule) þ taste sour þ will turn different indicators different colors þ corrode metals þ electrolytes (weak  strong) þ react with bases to form a salt and water þ pH is less than 7

6 Some Common Acids –sulfuric acid: most widely used chemical in the world, car batteries, production of fertilizers –phosphoric acid: make fertilizers and detergents –nitric acid: fertilizers and explosives –hydrochloric acid: stomach acid and to pickle (clean) metals

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9 HBrHBr H 2 CO 3H 2 CO 3 H 2 SO 3H 2 SO 3  hydrobromic acid  carbonic acid  sulfurous acid Acid Nomenclature Review

10 Properties of Bases  most produce OH - ions in water  taste bitter, chalky  change indicators a different color than acids  electrolytes  feel soapy, slippery  react with acids to form salts and water  pH greater than 7

11 Some Common Bases NaOHsodium hydroxide - lye NaOHsodium hydroxide - lye KOHpotassium hydroxide - liquid soap KOHpotassium hydroxide - liquid soap Ba(OH) 2 barium hydroxide - stabilizer for plastics Ba(OH) 2 barium hydroxide - stabilizer for plastics Mg(OH) 2 magnesium hydroxide - Milk of magnesia Mg(OH) 2 magnesium hydroxide - Milk of magnesia Al(OH) 3 aluminum hydroxide - Maalox (antacid) Al(OH) 3 aluminum hydroxide - Maalox (antacid)

12 Acid-Base Definitions

13 Arrhenius Acids and Bases –acids produce H + ions (or hydronium ions H 3 O + ) in aqueous solutions »only with hydrogens in very polar bonds

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15 bases – produce OH - ions in aqueous solutions »strong NaOH or KOH »weak (not very soluble in water, so even when saturated, not very concentrated) Ca(OH) 2 or Mg(OH) 2

16 Arrhenius acid is a substance that produces H + (H 3 O + ) in water Arrhenius base is a substance that produces OH - in water

17 Brønsted – Lowry Acids and Bases –others that don’t qualify as acid or base with Arrhenius definition but yet have acidic or basic properties –expands Arrehenius theory to include any proton (H + ) transfer »acids – proton (H + ) donor »bases – proton (H + ) acceptor a “proton” is really just a hydrogen atom that has lost it’s electron –conjugate acids and conjugate bases are compounds formed when a H+ ion is gained and a H+ is lost

18 A Brønsted-Lowry acid is a proton donor A Brønsted-Lowry base is a proton acceptor hydrogen ion donor ACID conjugate base hydrogen ion accepter BASE conjugate acid

19 The Brønsted definition means NH 3 is a BASE in water — and water is itself an ACID

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21 Lewis Acids and Bases –most general/encompassing definition –acids accepts a pair of electrons to form a covalent bond –bases donate a pair of electrons to form a covalent bond

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