Tag: chemistry

Questions Related to chemistry

Why corrosion is more seen in damp areas?

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Damp areas are deficient of light

  2. Damp areas provides air and water

  3. Both $A$ and $B$

  4. None of the above

Show answer
Correct Option: B
Explanation:

Damp areas alone supplies both the things air and water required for the rusting of iron.

Corrosion occurs due to:
a) action of water on the metal.
b) action of air on the metal.
c) action of temperature on the metal.

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. a, b

  2. b, c

  3. a, c

  4. all of the above

Show answer
Correct Option: A
Explanation:

An action of air and water gradually eats up the metal. This eating up of metals by the action of air and moisture on their surface is called corrosion.

Which of the following methods is suitable for preventing an iron frying pan from rusting?

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Applying grease

  2. Applying paint

  3. Applying a coating of zinc

  4. All of the above.

Show answer
Correct Option: C
Explanation:

We can prevent iron getting rusted by applying a coat of zinc or a thin coat of plastic helps to prevent rust. The process for coating metal like iron or steel with a thin zinc layer is known as galvanization.

The surface of some metals, such as iron, is corroded when they are exposed to moist air for a long period of time. This phenomenon is known as __________ .
chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Erosion

  2. Corrosion

  3. Rusting

  4. Both A and B

Show answer
Correct Option: B

Given,
$E _{Ag^{+}/Ag}^{\circ}  = +0.80V, E _{Co^{2+}/Co}^{\circ} = -0.28 V, E _{Cu^{2+}/Cu}^{\circ} = +0.34 V, E _{Zn^{2+}/Zn}^{\circ} = -0.76V$, 
Which metal will corrode to greater extent?

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. $Ag$

  2. $Cu$

  3. $Co$

  4. $Zn$

Show answer
Correct Option: D
Explanation:

Metal having much more positive potential will Oxidise less easily and coorrode slowly and vice-versa. So, Zinc will corrode fastly.

According to electrochemical theory of corrosion involves:

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. cathodic dissolution of metal

  2. cathodic deposition of metal

  3. anodic dissolution of metal

  4. anodic deposition of metal

Show answer
Correct Option: A
Explanation:

In corrosion $Fe^{2+}$ get oxidised to $Fe^{3+}$ which takes place on anode surface.

Anode: $Fe(s)\rightarrow { Fe }^{ 2+ }+2{ e }^{ - }$
Cathod:${ O } _{ 2 }+4{ H }^{ + }+4{ e }^{ - }\rightarrow { 2H } _{ 2 }O$
Overall:$2Fe(s)+{ O } _{ 2 }+4{ H }^{ + }\rightarrow 2{ Fe }^{ 2+ }+{ H } _{ 2 }O$
             ${ 4Fe }^{ 2+ }+{ O } _{ 2 }+(2+4x){ H } _{ 2 }O\rightarrow { 2Fe } _{ 2 }{ O } _{ 3 }.x{ H } _{ 2 }O+4{ H }^{ + }$
So,$Fe^{3+}$ get deposited on metal surface.

Which metal is usefull for protection of iron by corrosion?

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Aluminium

  2. Sodium

  3. Zinc

  4. Copper

Show answer
Correct Option: C
Explanation:

A thin layer of zinc coats other metals such as iron. It protects the iron from corrosion. Also since zinc is a more reactive metal it acts as a sacrificial metal. The oxygen in the air reacts with zinc to form zinc oxide, thus protecting the iron.

Which of the following will be most easily corroded in moist air?

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. $Zn$

  2. $Fe$

  3. $Ni$

  4. $Sn$

Show answer
Correct Option: B
Explanation:
When iron ( $Fe$ ) is exposed to moist air, it reacts with oxygen to form rust.

The formation of a rust is a very complex process, which is thought to begin with the oxidation of iron to ferrous ( iron"+2") ions.

Iron metal reacts in moist air by oxidation to give a hydrated iron oxide. This does not protect the iron surface to further reaction since it flakes off, exposing more iron metal to oxidation. This process is called rusting.

2 ml ethanoic acid was taken in test tubes - A, B and C. 2 ml, 4 ml and 8 ml of water was added to the test tubes A, B and C respectively. Which test tube will show clear solution?

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. only A

  2. only B

  3. only A and B

  4. all

Show answer
Correct Option: A

Iron and rust are the same things.

chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Iron and rust are different thing.

When iron $(Fe)$ undergoes corrosion it form iron oxide $(Fe _2O _3)$ which is nothing but a rust.