Question

Which of the following is a true statement about acids and bases

-an acid has a ph of 7.1
-An acid accord hydrogen ions
-A base has ph of 7
-a base gives off hydroxide ions

Answer 1

An acid has a pH lower than 7, while a base has a pH higher than 7.'A base gives off hydroxide ions' ,The correct statement is a.

Step-by-step explanation:

Acidic solutions have a pH lower than 7, while basic solutions have a pH higher than 7. Therefore, the statement 'An acid has a pH of 7.1' is false. An acid increases the concentration of hydrogen ions (H+) in a solution, which lowers the pH. The statement 'A base has a pH of 7' is also false. A base decreases the concentration of hydrogen ions and increases the concentration of hydroxide ions (OH-) in a solution, raising the pH. So, the correct statement is 'A base gives off hydroxide ions.' Bases release hydroxide ions, which can accept hydrogen ions to form water, reducing the solution's acidity.

Answer 2

According to Arrhenius concept:

An Acid is a substance which gives hydrogen ions (H⁺) when dissolve in water. Examples are HCl (Hydrochloric acid) , HNO₃ ( Nitric acid)

HCl ------- H⁺ + Cl⁻

A base is a substance which gives hydroxide ions (OH⁻) when dissolved in water. Examples are NaOH (Sodium hydroxide), KOH (Potassium hydroxide)

NaOH ------------ Na⁺ + OH⁻