Question

1. A solution is prepared by dissolving 0.23 mol of butanoic acid and 0.27 mol of sodium butanoate in water sufficient to yield 1.00 L of solution. The addition of 0.0O5 mol of HCI to this buffer solution causes the plH to drop slightly. The pH does not decrease drastically because the HCl reacts with the present in the buffer solution. The Ka of butanoic acid is 1.36x 10-3 A) H20 в) Нзо+ butanoate ion D butanoic acid AlE) This is a buffer solution: the pH does not change upon addition of acid or base 2. When titrating a weak monoprotic acid with NaOH at 25°C, the aA) pH will be less than 7 at the equivalence point. B) pH will be equal to 7 at the equivalence point CPH will be greater than 7 at the equivalence point. D) titration will require more moles of base than acid to reach the equivalence point. E) titration will require more moles of acid than base to reach the equivalence point 3. A 100.0 ml sample of 0.18 M HCIO4 is titrated with 0.27 M LIOH. Determine the plH of the solution after the addition of 50.0 mL of LIOH. HA 13.S KS A) 12.48 B) 0.68 C235 D) 152 E) 3.22 13.S u.S oH ya d 4. A 25.0-mL. sample of 0.150 M hydrocyanic acid is titrated with a 0.150 M NaOH solution Wht is the pH after 13.3 mL. of base is added? The Kg of hydrocyanic acid is 4.9 x 10-10 A) 9.04 B) 1.34 C)5.32 D) 9,37 E) 9.25 39 202 5. The solubility of lead(I) chloride is 0.45 g/100 ml. of solution. What is the K of PbCl? A. 4.9 x 10 0.S B.1.7x 10 C. 8.5 x 10 22 D. 4.2 x 10 Е. 2.6 х 104 Page 1 of 2

Answer 1

I butanoate in realt with Hel. butario ate thot Hot butanoic aud equivalence part 2 pH > 7 at rol 3 Tht Orors 0.15 3 nhclou = 0.1B Mx Oollet = 0.018 mol LiOH = 0.27m x 8.05 hit = 0. olenol. 45 nudoy lebt = 0.018-0.01 = 0.008 mol. total volone =001 +0.05 = 0.15L oooorral 0.034 Chclow] =CH20+) - pH = log [Hot] -10 1.52. (4) NHON = 0.15M4 0.025 Lt = 0.00375 mo. nNaOH = 0.15 M40.0133t = 0.001995 mol HCNTOH- CN +H₂O 0.00375 0.001995 o C -0.001995 -0.001995 +0.001995 E d. 001755 o 0.001995 [N-7 9.31+ log - Too 0.001995 I CHEN pla logka = 9:31 pH platlo 1 0.001755 - 36.9.27.