* not completed

. A Brønsted-Lowry acid is defined as ________________, while a Brønsted-Lowry base is defined as ________________.

an H⁺ donor; an H⁺ acceptor correct incorrect

an H⁺ acceptor; an H⁺ donor correct incorrect

an H⁺ donor; an OH^– donor correct incorrect

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. The weaker the acid, the _____________ the pK_a.

greater correct incorrect

smaller correct incorrect

pK_a does not change with changing acid strength. correct incorrect

* not completed

. Predict the approximate pK_a values of H₃PO₄, H₂PO₄^–, and HPO₄^2–.

approximately 4, 9, and 14, respectively correct incorrect

approximately 3, 8, and 13, respectively correct incorrect

approximately 5, 10, and 15, respectively correct incorrect

* not completed

. Identify the correct statement:

Metallic elements typically form acidic oxides; nonmetals typically form basic oxides. Elements exhibiting amphotherism form oxides that can react with acids and bases. correct incorrect

Metallic elements typically form acidic oxides; nonmetals typically form basic oxides. Elements exhibiting amphotherism react neither with acids nor with bases. correct incorrect

Metallic elements typically form basic oxides; nonmetals typically form acidic oxides. Elements exhibiting amphotherism form oxides that can react with acids and bases. correct incorrect

* not completed

. Iron(III) forms octahedral aquaions in acidic solutions. Identify the correct formula of the ion:

[Fe(H₂O)₆]³⁺ correct incorrect

[Fe(HO)₆]³⁺ correct incorrect

[Fe(HO)₆]^3– correct incorrect

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. From the list that follows, select the choices that would be Lewis acids:
(1) molecules that would complete an octet by accepting an electron pair;
(2) metal cations that form coordination bonds;
(3) molecules or ions with complete octets that can either expand their valence shells or rearrange their valence electrons to accept an additional electron pair.

Only the first choice would be a Lewis acid. correct incorrect

All choices would be Lewis acids. correct incorrect

Only the first and third choices would be Lewis acids. correct incorrect

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. "Formation of complexes can be viewed as a Lewis acid/base reaction." This statement is:

Incorrect. correct incorrect

Only partially correct, i.e., only the metal ion that forms the complex is a Lewis acid; there is no Lewis base. correct incorrect

Correct. correct incorrect

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. For each mole of H₃PO₄ and of Na₂HPO₄ mixed in aqueous solution:

approximately 2 mol of H₂PO₄^– are formed. correct incorrect

about 1 mol of H₂PO₄^– is formed. correct incorrect

No H₂PO₄^– is present in the solution. correct incorrect

* not completed

. If the K_b of pyridine, C₅H₅N, is 1.8×10^–9, then what is the K_a of its conjugate acid, C₅H₅NH⁺?

5.72×10^–5 correct incorrect

5.55×10^–6 correct incorrect

4.06×10^–10 correct incorrect

* not completed

. Find the correct statement:

Longer hydrogen bonds are weaker and more electrostatic in nature than shorter hydrogen bonds. correct incorrect

Hydrogen bond is a result of a strong interaction between a hydrogen atom bound to a very electropositive element and a lone electron pair on a neighbouring atom. correct incorrect

A short hydrogen bond can be expected to have a high degree of electrostatic character because the element with lone pairs has high electronegativity. correct incorrect