ZnO-Introduction, Physical Properties, Preparation, Chemical Properties, Structure, Uses, Practice problems, FAQs

Have you ever noticed that generally people going outside in summer apply some lotions or cream to protect them from the scorching sun heat and to protect them from harmful UV rays? That lotion is

generally known as sunscreen.

Do you know what is the major component present in sunscreen? There are many other ingredients but Zinc oxide is one of the common ingredients which is present there. Interesting right?

There are many such uses of ZnO in day-to-day life. You might wonder, the nail paint generally women apply on their nails to make them look beautiful contains ZnO.

There is a wide application of ZnO; for instance, zinc oxide is used in a wide range of goods, including make-up, rubber, and prescription drugs. X-ray apparatus.

Let us study some more about this important oxide of Zinc and some chemical reactions related to this oxide.

TABLE OF CONTENTS

What is Zinc Oxide?
Physical properties of ZnO
Preparation of ZnO
Chemical Properties of ZnO
Uses of ZnO
Practice Problems
Frequently asked questions-FAQs

What is Zinc Oxide?

An inorganic substance with the formula ZnO is zinc oxide. It comes in the form of an insoluble white powder. Numerous materials and goods, such as cosmetics, dietary supplements, rubber, plastics, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, meals, batteries, ferrites, fire retardants, and first-aid tapes, contain ZnO as an ingredient.

Although zinc oxide can be found in nature as the mineral zincite, most of it is made synthetically.

Physical Properties of ZnO

Physical Properties of ZnO at room temperature are mentioned in the table below:

Molecular Formula	ZnO
Molar mass	81.408 g mol^-1
Appearance	White Solid
Odour	Odourless
Density at room temperature	5.606 g cm^-3
Boiling point	2360 ℃
Melting Point	1975 ℃

Preparation of Zinc oxide (ZnO)

Burning zinc or calcining zinc carbonate, zinc nitrate, or zinc hydroxide can produce zinc oxide. The mentioned reactions are listed below;

2Zn(s)+O₂(g)2ZnO(s)

ZnCO₃(s)ZnO(s)+CO₂(g) ↑

2Zn(NO₃)₂(s)2ZnO(s)+4NO2(g) ↑+O₂(g) ↑

Zn(OH)₂(s)ZnO(s)+H₂O(aq)

Very pure zinc oxide is produced by combining zinc sulfate and sodium carbonate in a solution. Basic zinc carbonate is produced as a product, then zinc oxide is obtained when basic zinc carbonate is heated.

4ZnSO₄(s)+4Na₂CO³(s)+3H₂O(aq)ZnCO₃.3Zn(OH)₂(ppt)+4Na₂SO₄(s)+3CO₂(g) ↑

ZnCO₃.3Zn(OH)₂(s)+Heat₄ZnO(s)+3H₂O(aq)+CO₂(g) ↑

Chemical Properties of ZnO

The powdered zinc oxide is white. When heated, it turns yellow, and when cooled, its natural colour returns.

It is incredibly light and insoluble in water.

It reaches its sublime condition at 400°C.

It is an amphoteric oxide, it dissolves quickly in acids to produce zinc salts and in alkalies to produce zincates.

ZnO(s)+H₂SO₄(aq)ZnSO₄(s)+H₂O(aq)

ZnO(s)+2HCl(aq)ZnCl₂(s)+H₂O(aq)

ZnO(s)+2NaOH(s)Na₂ZnO₂(s)+H₂O(aq)

When heated in hydrogen above 400°C, it turns into metal.

ZnO(s)+H₂(g)Zn(s)+H₂O(aq)

Zinc oxide is also reduced to zinc by carbon.

ZnO(s)+C(s)Zn(s)+CO(g)

Cobalt zincate is produced when cobalt nitrate and zinc oxide are heated; this green mass is known as Rinmann's green.

2Co(NO3)₂(s)2CoO(s)+2NO₂(g)+O₂(g) ↑

ZnO(s)+CoO(s)CoZnO₂(s) or CoO.ZnO(s)

Uses of Zinc oxide (ZnO)

It serves as a coloring agent.

Over-the-counter medicines include ZnO.

It functions as a skin protector.

It serves as a sunscreen since it lessens and helps to avoid sunburn.

It is used to stop early skin ageing.

used in nail care items.

It functions as an ointment for diaper rash.
Between 50 and 60 percent of ZnO is consumed by the rubber sector. Stearic acid and zinc oxide are both utilized in the vulcanization of rubber. Rubber is additionally shielded from UV rays and fungus by the ZnO ingredient.
Breakfast cereals among other dietary items have zinc oxide added as a source of zinc, a necessary source of vitamin.

Filters for cigarettes often contain zinc oxide. Significant amounts of hydrogen cyanide (HCN) and hydrogen sulphide (H2S) are removed from tobacco smoke without altering its flavour by a filter made of charcoal impregnated with zinc oxide and iron oxide.

Practice Problems:

When ZnO is treated with_______________, it also produces a substance like cement; similar compounds are utilized in dentistry.

A. sulphuric acid
B. phosphoric acid
C. Hydrochloric acid
D. Hypochlorous acid

Answer: B
When treated with phosphoric acid, ZnO also transforms into a substance like cement; similar materials are employed in dentistry. Hopeite, Zn₃(PO₄)2.4H₂O, is a significant component of the zinc phosphate cement created by this process.

Calamine is a zinc oxide solution that contains around 0.5 percent __________.

A. MgO
B. Fe₂O
C. FeO
D. CaO

Answer: B)
Calamine is a combination of zinc oxide and around 0.5 percent iron(III) oxide (Fe₂O₃) that is used in calamine lotion. Calamine has previously been used to refer to two minerals, zincite and hemimorphite.

_______________is used in mouthwash products and toothpaste as an antibacterial agent.

A. ZnS
B. ZnO
C. MgO
D. BeO

Answer: B
By lowering the volatile gasses and volatile sulfur compounds (VSC) in the mouth, zinc oxide, a purported antibacterial agent used in toothpaste and mouthwash products, is said to manage foul breath by preventing the production of plaque and tartar.

Natural gas undergoes a pretreatment process that involves the use of zinc oxide (ZnO) to remove ____________.

A. Butane
B. Carbon dioxide
C. Methane
D. Hydrogen sulfide

Answer: D
After hydrogenating any sulfur compounds in natural gas before a methane reformer, which can poison the catalyst, zinc oxide (ZnO) is employed as a pretreatment step to eliminate hydrogen sulfide (H2S), which can be harmful to the catalyst. About 230-430 °C (446-806 °F) is the range at which the reaction that turns H2S into the water.

H₂S(g)+ZnO(s)H₂O(aq)+ZnS(s)

Frequently asked questions-FAQs

1. What do you understand by the term oxides?
Answer: Oxide is a chemical element that joins with the oxygen-based binary molecule. Most of the metals on the periodic table react with oxygen to generate oxides.

2. What kind of substance is ZnO?
Answer: ZnO has been widely used as a semiconducting channel layer in metal oxide-based thin-film transistors since it is an n-type semiconductor. n-type doping results from oxygen vacancies or zinc interstitials in the semiconductor's natural state. Other advantageous characteristics include strong room-temperature luminescence, high electron mobility, wide band gap, and superb transparency.

3. What function do ZnO nanoparticles serve?
Answer: An excellent antibacterial agent against harmful microbes is ZnO nanoparticles. Basically, the main mechanism of these metal oxide particles' antibacterial activity may be the observed active oxygen species they produce.

4. Can we consider Zinc oxide a conductor or not?
Answer: The group of transparent conducting oxides, which includes zinc oxide (ZnO), includes materials that can be utilized as transparent electrodes in heated windows or other electronic devices.

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