English

Observe the following diagram and write answers. 1. Name the method. 2. Explain the method. 3. Give two examples of this method. - Science and Technology 1

Advertisements
Advertisements

Question

Observe the following diagram and write answers.

  1. Name the method.
  2. Explain the method.
  3. Give two examples of this method.
Short Note

Solution

  1. The method is called electroplating.
  2. Explanation:
    a. Electroplating is the process in which a less reactive metal is coated on a more reactive metal by electrolysis.
    b. It protects the object made of reactive metal from corrosion. c. It also improves the appearance of the object.
  3. Silver plated spoons, gold plated ornaments are examples of electroplating.
shaalaa.com
  Is there an error in this question or solution?
Chapter 8: Metallugy - Answer the Following

APPEARS IN

RELATED QUESTIONS

Why do we apply paint on iron articles?


Explain why Iron sheets are coated with zinc during galvanization.


What is anodising? Give its applications.


Write a chemical equation to show the process of corrosion of iron.


The chemical reaction involved in the corrosion of iron metal is that of:
(a) oxidation as well as displacement
(b) reduction as well as combination
(c) oxidation as well as combination
(d) reduction as well as displacement


State two conditions for the rusting of iron.


Fill in the following blanks with suitable words:
Tiffin boxes are electroplated with .............. but car bumpers are electroplated with ............... to protect them from rusting.


What is corrosion?


Give the constituents and one use of brass.


 Name five methods of preventing rusting of iron.


Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.


Brass is an alloy of:
(a) Cu and Sn
(b) Cu and Pb
(c) Pb and Sn
(d) Zn and Cu


Four metals P, Q, R and S are all obtained by the reduction of their oxides with carbon. Metal P is used to form a thin layer over the sheets of metal S to prevent its corrosion. Metal Q is used for electroplating tiffin boxes made of metal S whereas metal R is used in making car batteries. Metals Q and R form an alloy called solder. What are metals P, Q, R and S? How have you arrived at this conclusion?


Name the metal which is a constituent of plant pigment?


What is corrosion? What are necessary conditions for corrosion?


State under what conditions corrosion is faster ?


No chemical reaction takes place when granules of a solid, A, are mixed with the powder of another solid, B. However when the mixture is heated, a reaction takes place between its components. One of the products, C, is a metal and settles down in the molten state while the other product, D, floats over it. It was observed that the reaction is highly exothermic.

(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.

(ii) Mention any two types of reactions under which above chemical reaction can be classified.


Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
 Reaction on anode region :

`F_e(s) → Fe^(2+) (aq) +2e^-`

 Reaction on anode region :

`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `

When Fe2+ ions migrate from anode region they react with ................... to form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.

`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `

A way to prevent rusting ..................................................................

 

 


Identify the process shown in the diagram and explain it in short


Find the odd man out:


Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.


Answer the following question.

List two properties of alloys.


Give reason.

A wooden article should be polished.


Explain the term – rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove the conditions for rusting.


Give a reason why rust turns moist red litmus blue.


State whether the statement given below is true or false. If false write the correct statement.

Graphite is a lustrous non-metal which conducts electricity.


Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?


Find the odd one out and give its explanation.


Give preventive methods by giving examples of corrosion?


Give the equation for the formation of rust.


State two conditions necessary for rusting of iron.


Copper objects lose their shine and form green coating of ____________.


The diagram shows the reaction between metal and dil. acid.

What is the reason for different behaviour of Mg in test tube B?


Marble’s popularity began in ancient Rome and Greece, where white and off-white marble were used to construct a variety of structures, from hand-held sculptures to massive pillars and buildings.

The substance not likely to contain CaCO3 is:


A man painted his main gate made up of iron, to

  1. prevent it from rusting.
  2. protect it from the sun.
  3. make it look beautiful.
  4. make it dust-free.

Which of the above statement(s) is/are correct?


Give an example of a chemical reaction for each of the following situations:

Sound is produced


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×