Which trio of electrolytes is listed for Use no Water?

• A. Sodium, Potassium, Lithium
• B. Sodium, Potassium, Calcium
• C. Sodium, Magnesium, Potassium
• D. Sodium, Chloride, Potassium

Answer: (A)

When a lab instruction says “Use no Water,” it means the reagents are supplied in a dry form and are used without dissolving them in water. The electrolytes best matched for this dry-use approach are the alkali metals that are commonly provided as stable dry salts: sodium and potassium. Lithium is included in many dry-reagent kits as well, making the trio of sodium, potassium, and lithium the appropriate set for a “Use no Water” instruction. Calcium and magnesium typically require aqueous buffers or complexing agents to function reliably, and chloride is usually handled in solution rather than as a dry, water-free reagent. So the group that fits the dry-use concept best is sodium, potassium, and lithium.