Tag: electroplating and its application

Questions Related to electroplating and its application

Which of the following methods is not used to coat metallic elements to prevent corrosion?

chemistry metals and non metals effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Electroplating

  2. Metal cladding

  3. Metal spraying

  4. None of the above

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Correct Option: D
Explanation:

Electroplating is the process of plating one metal onto another by hydrolysis, most commonly for decorative purposes or to prevent corrosion of a metal. Metal cladding is the bonding together of dissimilar metals. It is different from fusion welding or glueing as a method to fasten the metals together. In metal spraying a wide range of metals is sprayed onto the surface of another metal. All of these methods are used to prevent corrosion.

Rusting of iron is :

chemistry metals and non metals effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. an oxidation reaction

  2. a reduction reaction

  3. a redox reaction

  4. a displacement reaction

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Correct Option: C
Explanation:

Rusting of iron is a redox reaction because iron is oxidised from $0$ to $+3$ oxidation state and oxygen is reduced from $0$ to $-2.$

$4Fe+3O _2 \rightarrow 2Fe _2O _3$

Rust is a\an ________ salt.

chemistry metals and non metals effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. hydrated

  2. anhydrous

  3. acidic

  4. basic

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Correct Option: A,D
Explanation:

Rust general formula is $Fe _2O _3.nH _2O$. It is basic in nature.

Assertion: Zinc is coated on the iron to prevent corrosion in a process called galvanization.
Reason: Zinc is a stronger reducing agent than iron and is more easily oxidized than iron.
chemistry electrical conductivity of liquids effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

  2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false

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Correct Option: A
Explanation:

Coating of iron with zinc to prevent corrosion is called galvanization.
Steel is dipped in a bath of molten zinc. The zinc coated iron is called galvanized iron. Zinc $(E^o=-0.763 : V)$ is stringer reducing agent than iron $(E^o=-0.44 : V)$ and is more easily oxidized than iron . Thus during corrosion, Zn is oxidized instead of Fe.

When the lead accumulator is charged, it acts as:

chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. an electrolytic cell

  2. a galvanic cell

  3. a Daniel cell

  4. none of the above

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Correct Option: A
Explanation:

During the charging of a lead accumulator cell, the electical energy is stored in the form of chemical energy. Thus, the electrical energy derives non-spontaneous chemical reactions. Hence, during charging, the lead accumulator cell acts as an electrolytic cell.

When lead storage battery is charged:

chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. lead dioxide dissolves

  2. sulphuric acid is regenerated

  3. lead electrode becomes coated with lead sulphate

  4. the concentration of sulphuric acid decreases

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Correct Option: B
Explanation:

During charging of lead storage battery, sulphuric acid is regenerated. The net cell reaction during charging is $ PbS{ O } _{ 4 } +{ 2{ H } _{ 2 }O  }  \xrightarrow {  }  Pb  +  Pb{ O } _{ 2 }  +  2{ H } _{ 2 }{ SO } _{ 4 }  $

Hence, option B is correct.

Which of the following is/are true regarding rancidity?

chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. On keeping for long time, the oxidation of oils and fats, changes the taste and odour of food.

  2. To prevent rancidity, food is stored in air tight containers.

  3. Rancidity can also be prevented by addition of antioxidants.

  4. To prevent rancidity, packed food items are flushed with an inert gas like nitrogen.

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Correct Option: A,B,C,D
Explanation:

The following are true regarding rancidity. On keeping for long time, the oxidation of oils and fats, changes the taste and odor of food and makes them unfit for consumption. To prevent rancidity, food is stored in air tight containers. Rancidity can also be prevented by addition of antioxidants. To prevent rancidity, packed food items are flushed with an inert gas like nitrogen.

Number of Faradays involved in the net reaction of Lead accumulator is __________.

chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. 1

  2. 0.5

  3. 2

  4. cannot be predicted

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Correct Option: C
Explanation:

For lead accumulator battery, the oxidation reaction at anode  requires two moles of electrons. Similarly, the reduction reaction at cathode  requires two moles of electrons. Hence, the number of Faradays involved in the net reaction of Lead accumulator is 2.
Note: 1 Faraday is equal to the amount of charge on 1 mole of electrons.

During the charging of lead accumulator battery voltage varies from:

chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. $2.15$ V to $1.88$ V

  2. $1.88$ V to $2.0$ V

  3. $1.88$ V to $2.15$ V

  4. does not change

Show answer
Correct Option: C
Explanation:

When the lead accumulator battery is charged, the voltage range is 1.88 V to 2.15 V as the concentration of sulphuric acid varies from 5% to 40%.


Hence, option C is correct.

Calcium hydroxide $\xrightarrow {\Delta}$ Calcium oxide + water. Identify the type of chemical reaction:

chemistry chemical reactions effects of oxidation reactions in daily life corrosion of metals electroplating and its application

  1. Decomposition Reactions

  2. Neutralization Reactions

  3. Displacement Reactions

  4. Combination Reactions

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Correct Option: A