Advertisements
Advertisements
प्रश्न
Write a molecular formula for rust.
उत्तर
The chemical formula of rust is Fe2O3•xH2O.
APPEARS IN
संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Write two methods of preventing the rusting of iron.
Why do we apply paint on iron articles?
Which metals do not corrode easily?
Which of the following methods is suitable for preventing an iron frying pan from rusting?
Explain how painting of an iron gate prevents it from rusting.
What type of chemical reaction is involved in the corrosion of iron?
Fill in the following blank with suitable word:
The corrosion of iron is called ................
What is the corrosion of iron known as?
What is meant by 'rusting of iron'? With the help of labelled diagrams, describe an activity to find out the conditions under which iron rusts.
Name two metals which resist corrosion due to the formation of a thin, hard and impervious layer of oxide on their surface.
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
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?
Explain how the activity series accounts for each of the following:
tendency to corrosion
Explain with reason:
Roasting is carried out on sulphide ores and not on carbonate ores.
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.
Observe the following picture a write down the chemical reaction with the explanation.
Identify the process shown in the diagram and explain it in short
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Write three methods of preventing rusting of iron.
What is "rusting"? Describe with a labelled diagram an activity to investigate the conditions under which iron rusts.
Give reason.
Copper and brass utensils should be tinned.
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.
Write a short note on Alloying.
_______ is an alloy made from iron, carbon and chromium.
Stainless steel is an alloy of _______.
Bronze : _______ : : Stainless steel : Fe + Cr + C
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 |
What is rust?
Observe the following diagram and give answers.
- Name this method of prevention of corrosion.
- For prevention of which metal this method is used?
- What is used as anode in this method?
What is rust?
Give the equation for the formation of rust.
Which among the following alloys contain mercury as one of its constituents?
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:
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?
A man painted his main gate made up of iron, to
- prevent it from rusting.
- protect it from the sun.
- make it look beautiful.
- 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
In ______ process a layer of molten tin is deposited on metals.
