1.
The neutral value on the pH scale is
Correct Answer
B. Equal to 7
Explanation
The neutral value on the pH scale is equal to 7. This means that a substance with a pH of 7 is neither acidic nor basic. It is considered to be neutral. The pH scale ranges from 0 to 14, with values less than 7 indicating acidity and values greater than 7 indicating alkalinity. A pH of 7 represents a balance between acidity and alkalinity, making it neutral.
2.
Water dissociates into H+ and OH- ions
Correct Answer
B. To a small degree
Explanation
Water dissociates into H+ and OH- ions to a small degree. This is because water molecules can ionize into H+ and OH- ions through a process called self-ionization or autoprotolysis. However, this process is very limited, with only a small fraction of water molecules dissociating into ions at any given time. The majority of water molecules remain intact, making water a very weak electrolyte.
3.
The pH scale is
Correct Answer
A. A logarithmic scale
Explanation
The pH scale is a logarithmic scale because it measures the concentration of hydrogen ions in a solution. Each unit on the pH scale represents a tenfold difference in acidity or alkalinity. This means that a solution with a pH of 3 is ten times more acidic than a solution with a pH of 4, and a hundred times more acidic than a solution with a pH of 5. Therefore, the pH scale is not linear or exponential, but logarithmic in nature.
4.
What is the H+ of a solution if the pH is 3.5?
Correct Answer
B. 3.16 x 10 to the power -4
Explanation
The pH scale is a logarithmic scale that measures the acidity or alkalinity of a solution. A pH of 3.5 indicates that the solution is acidic. The concentration of H+ ions in an acidic solution is higher than in a neutral or alkaline solution. The answer 3.16 x 10 to the power -4 represents the concentration of H+ ions in the solution, with a negative exponent indicating a small value. Therefore, the correct answer is 3.16 x 10 to the power -4.
5.
A solution has a [H+] = 7.0 x 10 to the power -11. What is its pH?
Correct Answer
A. 10.15
Explanation
The given solution has a hydrogen ion concentration of 7.0 x 10^-11, which is a very low concentration. pH is a measure of the acidity or alkalinity of a solution and is defined as the negative logarithm (base 10) of the hydrogen ion concentration. By taking the negative logarithm of 7.0 x 10^-11, we get 10.15, which is the pH of the solution.
6.
Bases have a pH
Correct Answer
D. Greater than 7
Explanation
Bases have a pH greater than 7 because they release hydroxide ions (OH-) when dissolved in water. These hydroxide ions react with hydrogen ions (H+) in a solution, reducing their concentration and increasing the concentration of hydroxide ions. This shift in the balance of ions results in a higher pH value, indicating alkalinity. Therefore, bases typically have a pH greater than 7.
7.
An acidic solution has
Correct Answer
D. A greater concentration of hydrogen ions than hydroxide ions
Explanation
An acidic solution has a greater concentration of hydrogen ions than hydroxide ions. This is because an acid is a substance that donates hydrogen ions (H+) in a solution. Hydroxide ions (OH-) are found in basic solutions, where there is a greater concentration of OH- ions than H+ ions. Therefore, the correct answer is that an acidic solution has a greater concentration of hydrogen ions than hydroxide ions.
8.
The pH scale ranges from
Correct Answer
C. 0 to 14
Explanation
The pH scale is a measure of the acidity or alkalinity of a solution. It ranges from 0 to 14, where 0 represents highly acidic solutions, 7 represents neutral solutions, and 14 represents highly alkaline solutions. This scale is logarithmic, meaning that each whole number increase or decrease on the scale represents a tenfold change in acidity or alkalinity.