Which of the following salts when dissolved in water will form a solution that will change blue litmus to red?

Which of the following salts when dissolved in water will form a solution that will change blue litmus to red?

Answer Details

The salt that will change blue litmus to red when dissolved in water is NH₄Cl. This is because NH₄Cl undergoes hydrolysis in water to form NH₄OH and HCl. NH₄OH is a weak base and will react with water to produce NH₄⁺ and OH^- ions. The OH^- ions will increase the concentration of hydroxide ions in the solution, making it slightly basic. Litmus paper is an indicator that changes color in response to the pH of a solution. Blue litmus paper turns red in acidic solutions, and since the NH₄Cl solution is slightly basic, it will change the blue litmus paper to red.