Which of the following household liquids would be effective in treating someone with too much acid in the stomach?

Step 1: Analyze the question Too much stomach acid (hyperacidity) is treated with an antacid, which is a substance that neutralizes excess acid. Antacids are bases (alkaline), so we need the option with a pH well above 7.

Step 2: Explain the concept

• pH below 7 means acidic.
• pH of 7 means neutral.
• pH above 7 means basic (alkaline).

Neutralization: Acid + Base → Salt + Water

Stomach acid is hydrochloric acid (HCl), with a pH of about 1 to 3. To reduce it, we need a mild base that reacts with the HCl.

Step 3: Evaluate each option

• A. Salt solution, pH 7.0: Neutral, so it cannot neutralize acid.
• B. Tomato juice, pH 4.1: Acidic, so it would add more acid.
• C. Milk of Magnesia, pH 10.5: Basic. It contains magnesium hydroxide, Mg(OH)₂, which neutralizes HCl:

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

• D. Black coffee, pH 5.0: Acidic, so it would not help and may worsen the problem.

Step 4: Answer The correct option is C. Milk of Magnesia with pH 10.5.

Exam tip: For "treating excess stomach acid" questions, look for the base (pH above 7). Remember that Milk of Magnesia = Mg(OH)₂ = antacid. Other common antacids are sodium hydrogen carbonate (baking soda) and aluminium hydroxide. Note that a strongly basic substance (like NaOH) would be harmful, so antacids are always mild bases.