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Salt determination (Mohr)

Convert the result from a 10 mL aliquot of 500 mL solution to NaCl-equivalent content in the original sample.

    Food Lab · Mohr titration

    An educational model. It does not replace actual test conditions or safety procedures.

    Precipitation titration and aliquot factor

    From an aliquot to total content

    Multiply the chloride amount in the aliquot by the total-to-aliquot volume ratio to scale it to the original sample.

    The aliquot factor D=Vt/Va is the dimensionless ratio of total final volume to aliquot volume.

    Silver nitrate volume relates to chloride equivalents. With potassium chromate indicator, observe a pale reddish-brown endpoint after mixing.

    Convert chloride amount to NaCl mass, divide by sample mass and multiply by 100 to obtain mass %.

    Apply only supplied blank measurements. The educational indicator and pH conditions are not a verified representation of the entire current Food Code.

    NaCl-equivalent content does not mean all chloride was actually present as NaCl.

    An independent educational simulation. Not affiliated with or endorsed by HRD Korea, Q-net or MFDS. Virtual results do not establish food safety or guarantee exam success.

    Food Lab · Solutions & titration / principles and inquiry

    Salt determination (Mohr): experiment guide

    A titrated aliquot must be scaled to the whole test solution. Use the precipitation endpoint and aliquot factor to find NaCl-equivalent mass %.

    How does it work?

    Ag⁺ reacts with Cl⁻ in a 1:1 ratio to precipitate AgCl. The endpoint’s reddish brown shows excess silver ions reacting with chromate ions.

    Key relationship

    NaCl(%) = (V − V0) × N × f × 58.44 × (Vt/Va) × 100 / (1000 × m)

    Try this investigation

    1. Weigh, transfer quantitatively, make up to volume and filter. Take a 10 mL aliquot, choose an indicator and titrate with silver nitrate.
    2. Record three normal titrations using independent aliquots from the same solution. Do not invent a correction when no blank is provided.
    3. Preserve the normal records and compare with a calculation that omits the aliquot factor D=50.

    Interpreting your results

    What is the aliquot factor when 10 mL is titrated from 500 mL of test solution?

    500/10=50. Omitting this factor gives 1/50 of the correct NaCl-equivalent content.

    Assumptions and limitations

    This food-edu-v1 educational model does not assess real food safety. Unsuitable pH, color interference, bubbles and overtitration are invalid conditions. Separate silver and chromium waste into designated containers.