Why the blood pH in veins is more acidic?

Blood pH in veins is not more acidic. In fact, the pH of arterial blood is slightly more acidic than that of venous blood. The normal pH range for arterial blood is 7.35-7.45, while the pH range for venous blood is 7.35-7.45. This slight difference in pH is due to the fact that arterial blood has a higher oxygen content than venous blood. When oxygen is taken up by cells, it releases hydrogen ions, which can decrease the pH of the blood. Therefore, venous blood, which has a lower oxygen content, has a slightly higher pH than arterial blood.