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Potassium Iodide Formula – Structure, Properties, Uses, Sample Questions

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Potassium (K) is a chemical element and its atomic number is 19. Potassium is a silvery-white metal that examines enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure.

An Iodide particle is I. Compounds with iodine in proper oxidation state -1 are called iodides. In regular daily existence, iodide is generally a part of iodized salt, which numerous state orders. It might be a compound, medicine, and dietary enhancement. Iodide might be a halide anion.

What is Potassium Iodide?

Potassium iodide is an inorganic chemical compound and it’s chemical formula is KI. This compound is a metal-halide salt having an ionic bond between potassium cation (K+) and iodide anion (I). It is colourless and it appears as cubical crystals or white or powder granules. It has a saline taste and it is highly bitter in taste. 

Formula of Potassium Iodide

The chemical formula of Potassium Iodide is KI.

Preparation of Potassium Iodide

  • This compound can be prepared by mixing iodine with potassium hydroxide.

2K + I2  ⇢   2KI

  • And also, by reacting alcoholic KOH with Iodine to give Potassium Iodide along with Hydrogen and Oxygen.

2KOH + I2   ⇢   2KI + H2 + O2

Structure of Potassium Iodide

Potassium iodide contains one potassium cation (K+) and one iodide anion (I) and there exists an ionic bond between them. It is a colorless compound.

Structure of Potassium Iodide

Properties of Potassium Iodide

Physical Properties of Potassium Iodide:

  • The molecular weight of Potassium iodide is 166.0028 g/mol.
  • The density of Potassium Iodide is 3.12 g/cm3
  • The boiling point of Potassium Iodide is 1330 °C.
  • The melting point of Potassium Iodide is 681 °C.

Chemical properties of Potassium Iodide:

  • Potassium iodide can be oxidized into an I2 molecule when reacted with an oxidizing agent. 

2KI + Cl2 → 2 KCl + I2
4 KI + 2 CO2 + O2 → 2 K2CO3 + 2 I2

Uses of Potassium Iodide

  • Potassium iodide can be used as a nutritional supplement in the human diet and also for animal feeds.
  • It is the most common additive used to iodize table salt.
  • It is used to avoid the loss of iodine due to oxidation from salts.
  • It is used in the treatment of hyperthyroidism, it can help in shrinking the size of the thyroid gland and also decreases the number of thyroid hormones produced.
  • It helps in promoting hormonal balance.
  • It helps to filter out chlorides, bromides, fluorides, and mercury from cells and tissues.

Sample Questions

Question 1: How is potassium iodide prepared?


Potassium iodide (KI) is prepared when potassium hydroxide is reacted with iodine with a hot solution. It is used in the form of a saturated solution.

Question 2: What are the harmful effects of Potassium Iodide?


Unnecessary usage of potassium iodide can cause conditions like the trigger, Jod-Basedow phenomenon, hypothyroidism and hyperthyroidism. Also, it can cause sialadenitis, which is an inflammation of the salivary gland. It can causes rashes, and gastrointestinal disturbances. Also, potassium iodide compound is not good for people those who are having hypocomplementemic vasculitis and dermatitis herpetiformis.

Question 3: What happens to Copper sulphate when reacts with potassium iodide?


Copper sulphate when reacted with potassium iodide we get cuprous iodide (CuI), Iodine gas and also forms potassium sulphate.

2CuSO4 + 4KI  ⟶  2CuI+I2 +2K2SO4

Question 4: What happens if we consume potassium iodide?


If we consume potassium iodide it upsets our stomach. It can cause nausea, vomitings, abdominal pain and diarrhea. It should be taken after meals or it should be taken with food or milk unless doctor suggested to take it.

Question 5: What happens when Ozone reacts with potassium iodide?


When ozone is reacted with potassium iodide, we get potassium hydroxide, oxygen gas and iodine.

O3 + 2KI + H2O   ⇢    2KOH + I2 + O2

Question 6: What happens when potassium iodide is added to a lead nitrate?


When potassium iodide reacted with lead nitrate it gets lead iodide and potassium nitrate as,

2KI (aq)  +  Pb (NO3)2 (aq)    →    2KNO3 (aq)  +  PbI2 (s)

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Last Updated : 29 Apr, 2022
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