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प्रश्न
Find the odd man out:
विकल्प
Tinning
Anodization
Alloying
Froth floatation
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उत्तर
Froth floatation
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संबंधित प्रश्न
Why do we apply paint on iron articles?
Explain the term corrosion.
Explain how painting of an iron gate prevents it from rusting.
Choose the correct answer from the options given below:
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as
A. Smelting
B. Ore-dressing
C. Calcination
D. Bessemerisation
Explain why, iron sheets are coated with zinc.
State two conditions for the rusting of iron.
The process of depositing a thin layer of zinc on iron articles is called ______.
The corrosion of copper produces a ______ coating of basic copper carbonate on its surface.
______ and ______ are necessary for the rusting of iron.
What is the corrosion of iron known as?
Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?
A common metal which is highly resistant to corrosion is ______.
If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of ______.
No chemical reaction takes place when granules of a rusty-brown 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.
- What could the solids A and B be?
- What are the products C and D most likely to be?
- Write the chemical equation for the reaction between A and B leading to the formation of C and D. Mention the physical states of all the reactants and products in this equation and indicate the heat change which takes place.
- What is the special name of such a reaction? State one use of such a reaction.
- Name any two types of chemical reactions under which the above reaction can be classified.
Name the metal which is a constituent of blood pigment?
What is corrosion? What are necessary conditions for corrosion?
What is done to prevent corrosion of metals?
Write three methods of preventing rusting of iron.
Give reason.
A wooden article should be polished.
Give reason for the following:
A suspension of rust is basic in nature.
Stainless steel is an alloy of _______.
When one of the metals in an alloy is mercury the alloy is called _______.
Find the odd one out and give its explanation.
Find the odd one out and give its explanation.
Match the columns.
| Group A | Group B |
| 1) Electroplating | a) Pressure cooker |
| 2) Anodising | b) Silver plated spoons |
| c) Coating of tin on copper | |
| d) Coating of Zinc on iron |
Write the name.
An alloy of copper and tin-
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Write scientific reason.
On exposure to air, silver articles turn blackish after some time.
Explain concept with example/explain with the help of a balanced equation.
Corrosion
Draw a neat labelled diagram.
Anodizing
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?
Galvanisation is a process used to prevent the rusting of which of the following?
Explain the following:
Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
