Lufthansa
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Calculate the pH of a 200 mg cm-3 solution of chlorphenamine maleate solution.
Note: pKw = 14.00; pKa maleic acid = 1.90; pKb chloramphenamine = 5.00; Mw = 390.8 g mol-1; pH = ½ pKw + ½ pKa – ½ pKb

Please give your answer rounded to 2 d.p.

pH = Answer

how do you do this? Is the answer I get 5.45 correct?
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Borek
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5.45 would be reasonably correct for a monoprotic acid salt (assuming given pKa and pKb values).

Maleic acid is diprotic, and you can't ignore the second dissociation constant.
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Lufthansa
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(Original post by Borek)
5.45 would be reasonably correct for a monoprotic acid salt (assuming given pKa and pKb values).

Maleic acid is diprotic, and you can't ignore the second dissociation constant.
Thank you Borek

Sulfacetamide is known to undergo hydrolysis with a first order rate constant (k1) of 9 × 10-6 s-1 at 120°C (T1=393 K).
Using the following modification of the Arrhenius Equation, calculate the hydrolysis rate constant (k2) at 25°C (T2=298 K).
Arrhenius equation (mod.):
log (k2/k1) = (Ea(T2-T1)) / (2.303 × R × T2 × T1)
Please note that R = 8.314 J mol-1 K-1 and the activation energy (Ea) is 94 kJ mol-1.

Express your answer in index form, rounding the first box to 1 d.p.


for this question , do you get 9.4 x 10 power - 10 ?
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