Question

Which ions, if present in drinking water, would pose a significant health risk?

I. Pb2+
II. Hg2+
III. Cd2+
IV. Ca2+

A: I, II, and III only
B: II, III, and IV only
C: I, III, and IV only
D: I, II, III, and IV

Answer 1

Ions such as Pb2+, Hg2+, and Cd2+ in drinking water pose significant health risks and can lead to serious health problems, while Ca2+ is essential for health, indicating answer A as the correct choice.

Step-by-step explanation:

In drinking water, certain ions can pose a significant health risk if they are present. The ions that would pose a significant health risk if present in drinking water are Pb2+ (lead), Hg2+ (mercury), and Cd2+ (cadmium). These ions are known to be highly toxic and can lead to serious health problems if consumed. In contrast, Ca2+ (calcium) is not generally a health risk and is an essential mineral for human health; in fact, it provides benefits such as strong bones and teeth. Therefore, the correct answer to the question is A: I, II, and III only.