Which of the following statements is correct for the Bronsted-Lowry acid-base reaction
[tex]HCN+HCO_3^{-} \rightleftharpoons CN^{-}+H_2 CO_3[/tex]
A. [No correct response.]
B. [tex]HCO _3^{-}[/tex] is the conjugate base of HCN.
C. [tex]HCO _3{ }^{-}[/tex] and [tex]CN ^{-}[/tex] are a conjugate acid-base pair.
D. HCN is the conjugate acid of [tex]HCO _3^{-}[/tex].
E. [More than one correct response.]
Answer (2)
The Bronsted-Lowry reaction provided shows HCN acting as an acid and H C O 3 − as a base. The conjugate acid-base pairs are HCN/ C N − and H C O 3 − / H 2 C O 3 . After evaluating the statements, the correct answer is A: [No correct response].
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Identify the acid and base in the reaction: HCN is the acid, and H C O 3 − is the base.
Identify the conjugate acid-base pairs: HCN/ C N − and H C O 3 − / H 2 C O 3 .
Evaluate each statement to determine its correctness.
Conclude that none of the statements are correct, so the answer is: No correct response .
Explanation
Identifying Acids and Bases In the given Bronsted-Lowry acid-base reaction, we have: H CN + H C O 3 − ⇌ C N − + H 2 C O 3 We need to identify the acid, base, conjugate acid, and conjugate base to determine which of the given statements is correct.
Determining Acid and Base Roles In this reaction, HCN donates a proton (H+) to H C O 3 − . Therefore, HCN is the acid, and H C O 3 − is the base. On the reverse reaction, H 2 C O 3 donates a proton to C N − , so H 2 C O 3 is an acid and C N − is a base.
Identifying Conjugate Pairs Now, let's identify the conjugate acid-base pairs. A conjugate acid-base pair consists of two species that differ by only a proton (H+). - HCN (acid) and C N − (conjugate base) form a conjugate acid-base pair. - H C O 3 − (base) and H 2 C O 3 (conjugate acid) form a conjugate acid-base pair.
Evaluating the Statements Now, let's evaluate the given statements: 1. ' H C O 3 − is the conjugate base of HCN.' This is incorrect. H C O 3 − is a base, and C N − is the conjugate base of HCN. 2. ' H C O 3 − and C N − are a conjugate acid-base pair.' This is incorrect. They do not differ by only one proton. 3. 'HCN is the conjugate acid of H C O 3 − .' This is incorrect. HCN is an acid, and H 2 C O 3 is the conjugate acid of H C O 3 − .
Final Answer Since none of the provided statements are correct, the correct answer is 'No correct response'.
Examples
Understanding Bronsted-Lowry acid-base reactions is crucial in many chemical processes, such as buffer systems in our blood. For example, the bicarbonate buffer system ( H 2 C O 3 / H C O 3 − ) helps maintain the blood's pH within a narrow range (7.35-7.45). If the pH drops too low (acidosis) or rises too high (alkalosis), it can be life-threatening. The equilibrium between carbonic acid ( H 2 C O 3 ) and bicarbonate ( H C O 3 − ) helps neutralize excess acids or bases in the blood, ensuring proper bodily function. This reaction is similar to the one in the problem, where an acid donates a proton to a base, forming a conjugate base and a conjugate acid.
