Question 11 Which of the following statements about pH are true pH is a measure of hydrogen ion concentration A single unit of change in the pH sclae is equivalent to a 20% change in hydrogen ion concentration none of the choices are correct pH measure the alkalinity of a substance more than one of the choices are correct

The pH is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is indeed a measure of hydrogen ion concentration. A single unit change in the pH scale corresponds to a ten-fold (or ) change in hydrogen ion concentration, not a change. The statement that pH measures the alkalinity of a substance is partially true; pH can indicate alkalinity when the value is above 7, but it also measures acidity when the value is below 7. Therefore, saying that pH only measures alkalinity is misleading. Let's evaluate each statement:- "pH is a measure of hydrogen ion concentration" is true. The pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration.- "A single unit of change in the pH scale is equivalent to a change in hydrogen ion concentration" is false. A single unit change in pH represents a ten-fold change in hydrogen ion concentration.- "None of the choices are correct" is false because the first statement is correct.- "pH measures the alkalinity of a substance" is a partial truth. pH can indicate the alkalinity of a substance when the pH is above 7, but it also measures acidity when the pH is below 7.- "More than one of the choices are correct" is false because only the first statement is completely correct.