In rehydration, the pH of the deionized water solution is adjusted to approximately what value?

• A. 2.0
• B. 3.5
• C. 5.0
• D. 7.0

Answer: (B)

When preparing a rehydration solution, the pH is set to a mildly acidic level to keep the ingredients stable and dissolved. A target around 3.5 helps ensure the common rehydration components—glucose and electrolyte salts—stay in solution and remain stable during preparation and short-term use. It also provides some suppression of microbial growth without being harsh on the gastrointestinal lining. A pH as low as 2.0 would be too harsh and could degrade ingredients or irritate tissues; a pH around 5.0 is closer to neutral and might not offer the same stability for the mixture; and a neutral pH of 7.0 offers less benefit for solubility and storage stability. So, approximately 3.5 is the practical compromise.