ApproximatePKAexpandedChart

- Approximate pKa values(rounded to nearest 5 <0 H H O H R O H R O R H OH RNH3 H R2NH2 R3NH R2NH H2O RNH2 H 5 O RCOH NH4 ROH RC CH NH3 R2C C H 10

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H O R H H O H H H O R R O C R OH H A pproximate pK a values (rounded to nearest 5) RNH 3 ROH H 2 O CH 4 RCH 3 NH 3 RC CH R 2 CC H H < 0 5 NH 4 R 2 NH 2 R 3 NH RNH 2 R 2 NH RCOH O 10 15 25 35 45 50 Element effect periodic trend (when acidic hydrogen is bonded to a different element): C N O F Cl Br I increasing acidity increasing basicity This means that H 2 O will be a stronger acid than NH 3 which will be a stronger acid than CH 4 . Be careful when comparing acids and bases using this periodic trend to make sure that they have the same charge and hybridization! Example 1: You can’t compare NH 4 + and H 2 O and say that H 2 O is a stronger acid. You can compare NH 4 + and H 3 O + and say that H 3 O + is a stronger acid. Example 2: You can’t compare OH- and NH 3 and say that NH
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This note was uploaded on 11/23/2010 for the course CHEMISTRY Chem 51A taught by Professor Dr.susanm.king during the Fall '10 term at UC Irvine.

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