( \mathrm{Ba}(\mathrm{OH})_{2} ) is a ( \mathrm{Br} ) nsted-Lowry base because A ( \square ) ( B ) it is a hydroxide donor. C it is a proton acceptor. D it can dissolve in water
The Correct Answer and Explanation is:
The correct answer is:
C it is a proton acceptor.
Explanation:
According to the Brønsted-Lowry theory, an acid is defined as a substance that donates a proton (H⁺ ion), while a base is a substance that accepts a proton. This definition is broader than the Arrhenius definition, which only considers acids and bases in aqueous solutions and requires acids to produce H⁺ ions and bases to produce OH⁻ ions.
Barium hydroxide, Ba(OH)2\mathrm{Ba(OH)_2}Ba(OH)2, is a strong base that dissociates completely in water to produce barium ions Ba2+\mathrm{Ba^{2+}}Ba2+ and hydroxide ions OH−\mathrm{OH^-}OH−. While it is true that it contains hydroxide ions, its classification as a Brønsted-Lowry base is not based on the fact that it contains or donates OH⁻, but rather on the fact that the OH⁻ ions it releases can accept protons.
In a Brønsted-Lowry reaction, the hydroxide ion OH−\mathrm{OH^-}OH−, which results from the dissociation of barium hydroxide, acts as the base because it accepts a proton from an acid to form water:OH−+H+→H2O\mathrm{OH^- + H^+ \rightarrow H_2O}OH−+H+→H2O
This reaction demonstrates the proton-accepting nature of the base. Therefore, barium hydroxide is considered a Brønsted-Lowry base because the OH−\mathrm{OH^-}OH− ions it provides accept protons during acid-base reactions.
Option A is misleading because “hydroxide donor” is not a recognized concept in Brønsted-Lowry theory. Option B repeats A’s error. Option D is incorrect because the ability to dissolve in water is a physical property and does not define acid-base behavior in the Brønsted-Lowry context.
Hence, the correct explanation is that barium hydroxide acts as a Brønsted-Lowry base because it is a proton acceptor through the OH−\mathrm{OH^-}OH− ions it produces.
