The boron trihalides (except BF₃) hydrolyze completely to boric acid and the acid HX.
(a) Write a balanced equation for the reaction of BCl₃ with water.
(b) Calculate Δ_rH° for the hydrolysis of BCl₃ using data in Appendix L and the following information:
Δ_fH° [BCl₃(g)] = −403 kJ/mol; Δ_fH° [B(OH)₃(s)]= −1094 kJ/mol.

Data given in Appendix L

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TABLE 20 Species Aluminum Al(s) AICI 3(S) Al2O3(S) Barium BaCl₂(s) BaCO3(s) BaO(s) BaSO4(s) Beryllium Be(s) Be(OH)2(S) Boron BC13(g) Bromine Br(g) Br₂(e) Br₂(g) BrF3(g) HBr(g) Selected Thermodynamic A+Hº (298.15 K) (kJ/mol) 0 -705.63 -1675.7 -858.6 -1213 -548.1 -1473.2 -902.5 -402.96 111.884 0 30.91 -255.60 -36.29 Values* Sº (298.15 K) (J/K . mol) 28.3 109.29 50.92 123.68 112.1 72.05 132.2 9.5 51.9 290.17 175.022 152.2 245.47 292.53 198.70 A+Gᵒ (298.15 K) (kJ/mol) -630.0 -1582.3 -810.4 -1134.41 -520.38 -1362.2 0 -815.0 -387.95 82.396 0 3.12 - 229.43 -53.45