Final answer:
The concentration of bicarbonate increases as the pH increases. This is due to the buffering action of bicarbonate which absorbs hydrogen ions at higher pH levels, making the solution more alkaline.
Step-by-step explanation:
The concentration of bicarbonate in a solution is directly related to the pH of the solution. The pH scale measures the concentration of hydrogen ions (H+) in a solution, with the scale ranging from 0 to 14. Pure water has a neutral pH of 7.0. The bicarbonate buffer system in the human body helps maintain blood pH at slightly alkaline levels. When the pH increases above 7, indicating a more alkaline solution, the concentration of bicarbonate (HCO3-) typically increases. This is because bicarbonate acts as a buffer that can absorb excess hydrogen ions, thus preventing large swings in pH. Conversely, when the pH decreases, becoming more acidic, bicarbonate can donate hydrogen ions, helping to increase pH back towards neutral. Therefore, as the pH of water increases from 7 to 7.5, the concentration of bicarbonate would increase, aligning with option b)