Functional group CH3 CH2 CH CH2R 0.8 1.3 1.6 C=C 1.6 2.0 2.6 C≡C 1.7 2.2 2.8 C6H5 2.3 2.6 2.9 F 4.3 4.4 4.8 Cl 3.0 3.4 4.0 Br 2.7 3.4 4.1 I 2.2 3.2 4.2 OH 3.3 3.5 3.8 OR 3.3 3.4 3.7 OC6H5 3.8 4.0 4.3 OCOR 3.6 4.1 5.0 OCOC6H5 3.9 4.2 5.1 OCOCF3 4.0 4.4 — CHO 2.2 2.4 2.5 COR 2.1 2.2 2.6 COOH 2.1 2.3 2.6 COOR 2.0 2.3 2.5 CONR2 2.0 2.1 2.4 CN 2.1 2.5 3.0 NH2 2.5 2.7 3.0 NR2 2.2 2.4 2.8 NRC6H5 2.6 3.0 3.6 NR3+ 3.0 3.1 3.6 NHCOR 2.9 3.3 3.7 NO2 4.1 4.2 4.4 SR 2.1 2.5 3.1 SOR 2.6 3.1 — =O (aliphatic aldehyde) — — 9.5 =O (aromatic aldehyde) — — 10 M-H (metal hydride) — — 2999500000000000000♠−5 to 2998850000000000000♠−15