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

Zinc Iodide compound consists of elements Zinc and Iodine. Zinc is silvery-greyish brittle metal present in group-12 of the periodic table. It is the first element in group-12. Its atomic number is 30 and is represented by the symbol Zn. Zinc is one of the widely used metals. Iodine is a non-metallic, lustrous and solid element present in group-17 of the periodic table. It appears in dark-grey color. Its atomic number is 53 and is represented by the symbol I. In its group, Iodine is the highly electropositive and least reactive element.

What is Zinc Iodide?

Zinc Iodide is an inorganic compound made up of one Zinc atom and two Iodine atoms. Its molecular formula is ZnI₂. Zinc Iodide is manufactured by the reaction of Zinc and Iodine while refluxing ether. Zinc Iodide appears in white solid form which readily absorbs water from the atmosphere. Zinc Iodide exists in both anhydrous form and dihydrate form. The IUPAC name of Zinc Iodide is diiodozinc.

Structure of Zinc Iodide

Zinc Iodide Structure

Preparation of Zinc Iodide

Zinc Iodide is prepared by the reaction of Zinc with Iodine in refluxing ether or water. The chemical reaction of this is given by-

Zn + I₂ ⇢ ZnI₂

Properties of Zinc Iodide

• Zinc Iodide appears in the form of white powder.
• The molar mass/molecular weight of Zinc Iodide is 319.18 g/mol.
• The melting point of Zinc Iodide is 446° C.
• The boiling point of Zinc Iodide is 1150° C.
• Zinc Iodide density is 4.74 g/cm³.

Uses of Zinc Iodide

• Zinc Iodide is used as a catalyst in the conversion of methanol to triptane.
• In industrial radiography, Zinc Iodide is used as an x-ray opaque penetrant. 
• Zinc Iodide in combination with osmium tetroxide is used as a stain in electron microscopy.

Sample Questions

Question 1: Why Zinc Iodide is used in industrial radiography?

Answer:

In industrial radiography, Zinc Iodide is used as x-ray opaque penetrant. It helps to improve the contrast between the damage and intact composite.

Question 2: Is Zinc Iodide present in a rechargeable aqueous zinc-halogen cell?

Answer:

Yes. Rechargeable aqueous zinc-halogen cell includes an aqueous electrolytic solution that contains Zinc Iodide/ Zinc Bromide salt in both electrode components.

Question 3: Find the molecular weight of Zinc Iodide.

Answer:

Zinc Iodide consists of one Zinc atom and two Iodine atoms.

Atomic weight of Zinc element=65.38

Atomic weight of each Iodine element=126.90447

Molecular Weight of ZnI₂ = (1×65.38) + (2×126.90447)

=319.18 g/mol

Question 4: Is Zinc Iodide ionic or covalent compound?

Answer:

Zinc Iodide is an ionic compound. Ionic compound is formed between opposite electrostatic charges. Zinc is a metal with two positive ions i.e. Zn⁺² and Iodine is a non metal with a negative ion i.e. I^–. So it is an ionic compound.

Question 5: Is Zinc Iodide health hazardous?

Answer:

Yes, Zinc Iodide is health hazardous. It causes eye and skin burns. May cause severe damage to the digestive tract and also cause allergic respiratory reaction.

Question 6: How Zinc Iodide is prepared?

Answer:

Simply Zinc Iodide is prepared by reacting Zinc with Iodine in aqueous solution (or) refluxing ether.. It’s chemical formula is ZnI₂.