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Question about Main Inorganic Compounds

Sciences

UNICISAL

Main Inorganic Compounds

Medium

(UNICISAL 2013) - Question Medium of Sciences

In the solutions used in laboratories, the concentrations of ions $$\mathrm{H}_{3} \mathrm{O}^{+}$$ are usually small and a simple way to express the hydrogenionic concentration of a solution is through pH. Solutions of weak acids and bases present, in solution, an equilibrium between the various particles and, in this case, we have the equilibrium constant, that is, the ionization constant. A solution of $$1.10^{-3} \mathrm{mol}^{-1}$$ of bromoacetic acid $$\left(\mathrm{BrCH}_{2} \mathrm{CO}_{2} \mathrm{H}\right)$$ has an ionization constant equal to $$6.3.10^{-5} \mathrm{e}$$ and a solution of $$1.10^{-3} \mathrm{mol}^{-1}$$ of 4-chlorobenzoic acid $$\left(\mathrm{ClC}_{6} \mathrm{H}_{4} \mathrm{CO}_{2} \mathrm{H}\right)$$ has an ionization constant of $$1.0.10^{-4}$$. Given the following statements, I. 4-chlorobenzoic acid has a higher $$\mathrm{pH}$$ than bromoacetic acid. II. Bromoacetic acid is weaker than 4-chlorobenzoic acid. III. Since the concentrations are equal, both acids have the same $$\mathrm{pH}$$. IV. Bromoacetic acid has a higher $$\mathrm{pH}$$ than 4-chlorobenzoic acid. v. 4-chlorobenzoic acid is weaker than bromoacetic acid. It is verified that only ii and iv are correct.
a.
ii e iv.
b.
iii, iv e v.
c.
i, ii e iii.
d.
i, ii e v.
e.
iii.

Answer sheet:

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