Question

question 9 of 10 which of the following is an example of a conjugate acid - base pair? a. hcl and hbr b. h₂s and hs⁻ c. no₂ and no₂⁻ d. hf and h⁺

Explanation:

A conjugate acid - base pair consists of two species that differ by a single proton (\(H^{+}\)).

• For option A: \(HCl\) and \(HBr\) are two different acids, not related by a proton transfer.
• For option B: \(H_{2}S\) (acid) can lose a proton (\(H^{+}\)) to form \(HS^{-}\) (base). So, \(H_{2}S\) and \(HS^{-}\) are a conjugate acid - base pair.
• For option C: \(NO_{2}\) is a neutral molecule. To be part of a conjugate acid - base pair, there should be a proton transfer relationship. \(NO_{2}\) and \(NO_{2}^{-}\) do not have a proton transfer relationship in the context of acid - base chemistry (as \(NO_{2}\) is not an acid that donates a proton to form \(NO_{2}^{-}\) in the Brønsted - Lowry sense).
• For option D: \(HF\) is an acid, but \(H^{+}\) is just a proton. A conjugate acid - base pair must have two species that are related by a proton transfer where one is an acid (donates \(H^{+}\)) and the other is its corresponding base (formed after losing \(H^{+}\)). \(HF\) and \(H^{+}\) do not fit this definition.

Answer:

B. \(H_{2}S\) and \(HS^{-}\)