Question

(1) The Brønsted-Lowry conjugate acid / conjugate base pair in the forward direction for the following equilibrium is, HCN (aq) + NO2 (aq) + HNO2 (aq) + CN (a) HCN, NO, (b) NO, , HNO2 (C) HNO, CN (4) CN, HCN (2) HNO, NO, (1) HCN, CN (2) The pH of 5.0 x 10* M aqueous solution of calcium hydroxide is (a) 10.7 (b) 5.4 (c) 11.0 (d) 3.3 (e) 8.6 (1) 3.0 (3) Assuming that any strong base encountered in the following selections is completely soluble, which of these are buffers, possibly after reaction? (1) 2.00 mmoL HI /4.00 mmoL NH; (2) 5.00 mmol NaHSO3 / 4.00 mmol Li,SO3 (3) 3.00 mmoL HNO3 74.00 mmoL NH; (4) 2.00 mmol Ca(OH)2 / 4.00 mmoL HNO2 (a) 3 only (b) 1,4 (@) all except 4 (d) 2,3 (e) all are buffers (1) 1,4

Answer 1

A conjugate acid base pair differs by a proton (H+) HON cap + Noz cap → Acid base HNO₂ cup conjugate acid + CN cap Conjugate base pair in yosward direction is so, conjugate acid I conjugate base (c) HNO2 , CN- Ca (OH) → Ca2+ + 204- [OH-] = 2X5.0 x 10M = 1x10²M por = -log [OH-] = - dog (1x103) = 3 pH = 14-3 = 11.0 (C)