With the help of the DH values given in Tables 3-1 and 3-4, calculate the H values

With the help of the DHº values given in Tables 3-1 and 3-4, calculate the ΔHº values for addition of each of the following molecules to ethene, using 65 kcal mol^-1 for the carbon – carbon π bond strength.

(a) Cl₂

(b) IF (DHº = 67 kcal mol^-1)

(c) IBr (DHº = 43 kcal mol^-1)

(d) HF

(e) HI

(f) HO – Cl (DHº = 60 kcal mol^-1)

(g) Br – CN (DHº = 83 kcal mol^-1; DHº for C_sp3 – CN = 124 kcal mol^-1)

(h) CH₃S – H (DHº = 88 kcal mol^-1; DHº for C_sp3 – S = 60 kcal mol^-1)

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Table 3-1 Bond-Dissociation Energies of Various A-B Bonds in the Gas Phase [DH° in kcal mol- (kJ mol-1)1 B in A-B A in A-B -H -F -CI -Br -I -OH -NH, H- 104 (435) 136 (569) 103 (431) 87 (364) 71 (297) 119 (498) 108 (452) CH3- 105 (439) 110 (460) 85 (356) 70 (293) 57 (238) 93 (389) 84 (352) CH;CH,- 101 (423) 111 (464) 84 (352) 70 (293) 56 (234) 94 (393) 85 (356) CH;CH,CH,- 101 (423) 110 (460) 85 (356) 70 (293) 56 (234) 92 (385) 84 (352) (CH;),CH- 98.5 (412) 111 (464) 84 (352) 71 (297) 56 (234) 96 (402) 86 (360) (CH3);C- 96.5 (404) 110 (460) 85 (356) 71 (297) 55 (230) 96 (402) 85 (356) Note: (a) DH° = AH° for the process A-B → A + ·B. (b) These numbers are being revised continually because of improved methods for their measurement. (c) The trends observed for A-H bonds are significantly altered for polar A-B bonds because of dipolar contributions to DH°.