A 50% citric acid solution is commonly used as an activating reagent in water purification protocols. The following preparation yields 100 ml of solution, which is sufficient for most home applications.

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Equipment

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• Digital scale (0.1 g precision recommended)

• 400 ml or 500 ml borosilicate glass measuring beaker with (100 ml) graduations

• Borosilicate glass stirring rod (recommended)

• 100 ml amber glass storage bottle with a secure cap (dropper bottle preferred)

 

A larger measuring beaker provides sufficient space to prepare and mix the solution comfortably without spilling.

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Ingredients

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• 50 g food-grade citric acid powder (preferably anhydrous, ≥99.5% purity, or the highest purity available)

• Purified or distilled water

 

Preparation

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1. Weigh 50 g of citric acid powder using the digital scale.

2. Transfer the powder into the borosilicate glass measuring beaker.

3. Slowly add purified or distilled water until the final volume reaches exactly 100 ml.

4. Stir using the borosilicate glass stirring rod until all crystals have completely dissolved. Alternatively, gently swirl the beaker until the solution is fully dissolved.

5. Transfer the finished solution into the amber glass storage bottle and seal securely.

 

The finished solution should be clear and colourless, with no visible crystals remaining.

 

Storage

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Transfer the finished solution into the amber glass storage bottle and close the cap securely.

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• Label the bottle clearly as "50% Citric Acid Solution."

• Store away from direct sunlight and excessive heat.

• Keep out of reach of children and pets.

 

Technical Notes

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• Food-grade citric acid is available from different manufacturers. Choose a product with the highest available purity and intended for food or laboratory use.

• Anhydrous citric acid is generally preferred for consistency, although food-grade citric acid monohydrate may also be used for this preparation.

• Always prepare the solution using clean borosilicate glass equipment to help minimise contamination and maintain solution quality.