Question

When a person with excess stomach acid takes an antacid, the pH of that person's stomach changes?

1) from a low value to a value nearer 7
2) from 7 to a much higher value
3) from a low value to an even lower value
4) from a high value to a lower value

Answer 1

Taking an antacid neutralizes stomach acid, increasing the pH from a low value (acidic) to a value closer to neutral (7), providing relief from discomfort like heartburn.

Step-by-step explanation:

When a person with excess stomach acid takes an antacid, the pH of that person's stomach changes from a low value to a value nearer 7. The stomach typically has a strongly acidic pH of 1 to 2, due to the presence of hydrochloric acid (HCl). Antacids, which are bases like calcium carbonate (CaCO3), neutralize this acid, increasing the pH closer to a neutral level.

The antacid reacts with the HCl in the stomach and forms products, including water, which helps to neutralize the acidic environment. This reaction increases the pH level, alleviating discomfort associated with excess acidity, such as heartburn. It is important to note that the pH scale is logarithmic, meaning that each whole pH value change represents a tenfold increase or decrease in H+ ion concentration, which is why antacids are effective in quickly increasing the pH.