Final answer:
The statement that reveals a misunderstanding in the client's education about ferrous sulfate liquid preparation is the intent to take the iron with milk to enhance its effectiveness, as milk can interfere with iron absorption.
Step-by-step explanation:
A nurse has instructed a client about taking ferrous sulfate liquid preparation. Among the options provided, the statement by the client that indicates the need for additional education is: I should take the iron with an antacid to prevent gastric distress.
This is because antacids can increase the pH level in the stomach, making it more alkaline, which decreases iron absorption. Acidic pH of the gastrointestinal tract is favorable for iron absorption as it reduces ferric iron (Fe³+) to ferrous iron (Fe²+), which is more soluble and more readily absorbed. Conversely, the presence of milk can interfere with iron absorption due to the binding of iron to calcium and other components in milk. Therefore, option c - I'll consume the iron supplement with a glass of milk to enhance its effectiveness - also indicates a misunderstanding.