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22 Chemistry of the Nonmetals Solutions to Exercises (b) 30 valence 15 e- pairs H H H H B H H B H H + + B H + + N N N N N N B B B + B B + H N H H N H H N H H H H The structure with nonbonded pairs minimizes formal charge, but these electrons are almost certainly delocalized about the six-membered ring, mimicking the bonding in benzene. (c) n = PV RT = 1.00 atm 273 K 2.00 L 0.08206 mol L - K - atm = 0.08929 = 8.93 X 10⁻² mol 0.08929 mol NH₃ 2 mol (BH)₃(NH)₃ 1 6 mol NH₃ mol (BH)₃(NH)₃ = 2.3956 = 2.40 g (BH)₃(NH)₃ 22.104 (a) + 6Zn(s) + 2AsH₃(g) + 6ZnSO₄(s) + 2AsH₃(g) 2As(s) (b) 2[As(s) As³⁺(aq)+3e⁻] (Na+ is a spectator ion in this reaction) (c) As₂O₃(s) + H₂S(g) HCI As₂S₃(s) + can be thought of as a catalyst in this reaction. It is necessary for the reactions to proceed, and is probably consumed and then reformed. 691