Final answer:
A city's water treatment must meet MCLG which is True, the statement about ion exchange in water softening is False, consumption safety of hard water is also False, and using osmosis (specifically reverse osmosis) to purify water is True.
Step-by-step explanation:
Categorizing the following statements as True or False:
A city's water treatment process must reduce contamination to levels at or below the MCLG (Maximum Contaminant Level Goal) is True. MCLG refers to the level below which there is no known or expected risk to health, and water treatment facilities work to ensure contaminant levels are at or below this.
For every calcium ion that will attach to the zeolite in the water softening process, two sodium ions will be removed from the zeolite is False. It is the opposite; for every calcium ion (Ca²+) or magnesium ion (Mg2+) that is attached to the zeolite, two sodium ions (Na⁺) are released into the water to maintain charge balance.
It is not safe to consume hard water is False. Most ions in hard water, like calcium and magnesium, are not harmful and can be consumed safely in moderation.
Osmosis can be used to purify water is True. While the statement should refer specifically to 'reverse osmosis,' this process is indeed used to purify water by removing dissolved ions and other impurities.
These clarify the principles behind the water treatment process, ion exchange in water softening, and the safety of consuming hard water.