Predict the approximate pH for aqueous Ba(NO3)2 solution.
options:
basic ,
neutral ,
acidic
The correct answer and explanation is:
The correct answer is neutral.
Barium nitrate, Ba(NO3)2, is a salt formed from the reaction of a strong base, barium hydroxide (Ba(OH)2), and a strong acid, nitric acid (HNO3). When Ba(NO3)2 dissolves in water, it dissociates completely into Ba²⁺ and NO3⁻ ions. The key point to consider here is the nature of these ions in water.
- Ba²⁺ (Barium ion): The barium ion is a metal cation that does not hydrolyze (react with water) significantly to produce H⁺ or OH⁻ ions. Therefore, it does not affect the pH of the solution.
- NO3⁻ (Nitrate ion): Nitrate is the conjugate base of a strong acid (HNO3). Conjugate bases of strong acids are weak bases and do not undergo hydrolysis in water to any appreciable extent. Hence, the nitrate ion also does not influence the pH of the solution.
Since neither the Ba²⁺ ion nor the NO3⁻ ion significantly alters the concentration of hydrogen ions (H⁺) in the solution, the solution will not be acidic or basic. The pH of the solution will remain around 7, which is considered neutral.
To summarize, the dissolution of Ba(NO3)2 in water does not result in the formation of acidic or basic species. Therefore, the pH of an aqueous Ba(NO3)2 solution is approximately neutral.