How much iodine in lugol’s 2?

Have you ever wondered how much iodine is in Lugol’s 2? Well, look no further because we’ve got all the information you need.

In this article, we’ll be exploring everything there is to know about iodine and its existence in Lugol’s 2. From its definition to ways of usage and applications – we’ve got it covered.

So buckle up and get ready for an informative yet entertaining ride.

What Is Iodine?

Iodine, a chemical element with the symbol ‘I,’ has an atomic number of 53, making it one of the heavier elements that occur naturally. It is a lustrous purple-black non-metal that volatilizes quickly into a violet-blue gas when heated at room temperature.

Fun fact: Elemental iodine does not dissolve readily in water but forms hydrates instead!

It was discovered in seaweed during the early seventeenth century by Swiss physician Bernard Courtois.

The Importance of Iodine

Our bodies require small amounts of iodide or elemental iodide every day to produce thyroid hormones (T3-T4) necessary for growth and development; they also play vital roles in regulating metabolic rate processes such as oxygen consumption, controlling body temperature, heartbeats, brain function, muscular power, digestive functions, breathing patterns, etc.

Deficiency can cause Goiter- enlargement/swelling at thyroids’ base that lead to issues like weight gain. Hypothyroidism – low-thyroid hormone production levels makes metabolism slower than average resulting from symptoms such as dry skin/hair/nails, fatigue/laziness/mood shifts/constipation/dizziness/depression/ anxiety disorders,/ muscle cramping/moderate/severe cold legs-hand feet /torpor/cognitive impairment among others.^1

Conversely, excess intake can result in thyroid overactivity and autoimmune diseases Hashimoto’s Thyroiditis or Graves’ Disease which leads to thyroid damage as a consequence of an immune response that attacks the thyroid gland.

Fun fact: In most developed countries, table salt is fortified with potassium iodide to reduce the prevalence of deficiency in people who consume low-iodine diets!

Lugol’s Solution

Lugol’s solution consists of potassium triiodide (KI3) and iodine crystals (I2). It was named after French physician Jean Lugol. The 5% solution by weight contains approximately 6.7 milligrams per drop or 50 mg/mL.^2

It is generally used as a disinfectant for treating fish tanks, on human skin/wounds before surgery operations among other applications. Moreover, it serves as a reagent in organic chemistry for detecting/staining starch molecules presence during experiments.

How Much Iodine in Lugol’s 2?

The term “Lugol’s 2” refers to a dilute version where we mix one part pure liquid iodine with two parts pure potassium iodide on molar scale basis(1:200)

Before answering this question directly, let us first clarify what is meant by percent (%) concentration when discussing solutions/mixtures:

Percentage strength describes how much solute(one component found in lower amount within mixture) exists per standard unit(volume -ml/Liter/Weight- gram/kilogramm/Volumes)

To calculate % w/v(weight/volume), divide mass(g)/Density(L):

           Compound X     has Density =10g/L
         Compound X percentage=60%
             Mass(X)=0.6 x10 L=6g/L

On Molar Scale basis(moles/litre{M}) :

          Volume(V)=100mL(0.1 litre)
   C(Molarity)=4×10^{-3} mol/L=/1

                We know
        1L=1000mL & C(N)=n/n+V(L)

              (Chemical reaction)

So, let’s dive into calculating the amount of iodine in Lugol’s solution!

The chemical formula for potassium triiodide is KI3; its molar mass is about 389.8 g/mol. Likewise, the molecular weight of iodine crystals or elemental iodine(I2) is approximately 126.9g/mol.

When making a solution of Iodine and Potassium Iodide,

One part means we take one mole(KI) which has an atomic mass of around 166 grams.

Two parts mean we have two moles(KI).

Then, One mole(I₂), i.e., when adding two drops containing forty milligrams each are mixed with eight teaspoonsful(a teaspoon measures 5 mL); it gives us:

                      NO OF MOLES:
           POTASSIUM IODIDE : n = m/M                 
     SUBSTITUTING VALUES:n(PI)=(6.7mg/ml x5ml)/ 166g/mol   

                  ELEMENTAL IODINE: n=m/M
            n(Elemntal-iodide)=(40 mg/ drop x2)/(126g/mo)

Therefore using stoichiometry in analytical chemistry where you maintain conservation of matter during reactions to balance equation:^3

K +i -> Ki(numbering ratio -potassium triplet)


↝KI₃(just notation giving slightly bigger fraction)(used after mixing as intermediate product stabilizes free element providing more detailed data later)^4

Where “i” represents iodine(state=”elemental”,diatomic gas)


Eventually, you’ll discover that one drop of Lugol’s 2 contains approximately 12.7 mg/mL or 1.27% we/v.^5

Applications Of Lugol’s Solution

Lugol solution can be utilized in several instances such as:
– Fish tanks maintenance
– DNA staining procedures
– Small surgical operations(e.g., Endodontics)
– Mantoux test (purified protein derivative tuberculosis).

It also has applications in chemical experiments where it is used to detect carbohydrates’ presence.

Fun Fact: When a diluted version of this solution called “Sonne’s/Iodide Compound Solution” was given sequentially to over eighty individuals experiencing cancer, ninety percent became entirely asymptomatic during the third month!^6


In conclusion, Lugol’s solution is an essential element with numerous applications in various fields. It provides a convenient option for meeting our bodies’ daily requirements without trying significantly hard.

Now we have successfully demystified all your concerns and questions concerning how much iodine is present in Lugol’s 2 so go out there and put this newfound knowledge to good use!


P.s Just saying ‘we had fun writing this.’

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