Question

07 Question (1 point) See page 696 Gifblaar is a small South African shrub and one of the most poisonous plants knownbecauseit contains fluoroacetic acid (FCH2COOH), which has a pk of 2.59. 1st attempt See Periodic Table Calculate the initial concentration of fluoroacetic acid in a solution that has the same pH as a 0.00875 M solution of HCI. 10 OF 13 QUESTIONS COMPLETED < 07/13 > SUBMIT ANSWER

Answer 1

pH of HCl is given by:

pH = -log [H⁺]

pH = -log (0.00875)

pH = 2.06

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Hence, Concentration of H⁺ in the acid solution:

[H⁺] = 10^-pH

[H⁺] = 10^-2.06

[H⁺] = 0.00875 M

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Given that, pKa of acid: pKa = 2.59

Therefore, Ka = 10^-pKa = 10^-2.59 = 2.57 x 10^-3

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Therefore, Initial concentration of the fluoroacetic acid is given by:

[acid] = [H⁺]²/Ka

[acid] = (0.00875)² / (2.57 x 10^-3 )

[acid] = 0.0298 M ----------- (answer)