Anonymous asked in Science & MathematicsChemistry · 1 decade ago

How do you lower the freezing point of water to -12C?

want to know how much and of what substance to add to 1 liter of water to lower it's freezing point to about -12C - ideally it would be non toxic - but preferrence is on ease to mix the substance in and cost (table salt doesn't work for my application) - the end solution must be clear. Thanks

2 Answers

  • maussy
    Lv 7
    1 decade ago
    Favorite Answer

    I would suggest you Calcium chloride

    effectively CaCl2 ---> Ca++ +2Cl- (1 molecule = 3 ions)

    and 1 mole of CaCl2 gives 3 osmoles

    1 osmole lowers the melting point of water by 1.85°C

    To lower the melting point by 12C you need = 6.48 osmoles

    in molarity of CaCl2 it is equal to 6.48/3 = 2.16molar solution

    A mole of CaCl2 = 40+2*35.5= 111g

    this corresponds to 111*2.16 = 240g/L

  • 1 decade ago

    Instead of using table salt, try using Magnesium Chloride, this will get you around -15 deg. C.

    Check this out for a list of more common salts.

    Source(s): Chem Teacher
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