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प्रश्न
When one of the metals in an alloy is mercury the alloy is called _______.
विकल्प
amalgam
sodium amalgam
zinc amalgam
all the above
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उत्तर
When one of the metals in an alloy is mercury the alloy is called amalgam.
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संबंधित प्रश्न
Give two examples of alloys with their chemical composition.
Explain the term corrosion.
Give reasons:
Platinum, gold and silver are used to make jewellery.
What special name is given to the corrosion of iron?
The chemical reaction involved in the corrosion of iron metal is that of ______.
______ and ______ are necessary for the rusting of iron.
Why is an iron grill painted frequently?
Explain why, though aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.
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?
Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.
In stainless steel alloy, iron metal is mixed with ______.
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.
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?
Bronze is an alloy of ______.
What is corrosion? What are necessary conditions for corrosion?
What is done to prevent corrosion of metals?
What are the adverse effects of corrosion?
Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.
Give reason.
An iron article should be given a coat of paint
Give a reason why rust turns moist red litmus blue.
_______ is an alloy made from iron, carbon and chromium.
Corrosion of silver causes a black layer of _______.
Stainless steel is an alloy of _______.
Write the name.
An alloy of copper and tin-
Write the name.
Method used to present corrosion of copper.
Write scientific reason.
Anodization method is useful for prevention of the corrosion of the aluminium.
Complete flow chart given below.
Write a molecular formula for rust.
Observe the following diagram and write answers.
- Name the method.
- Explain the method.
- Give two examples of this method.
State two conditions necessary for rusting of iron.
Amalgam is an alloy of ____________.
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?
Explain the following:
Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate.
Explain the chemical reactions in rusting of iron.
| A process of forming a thick oxide of aluminium when aluminium is exposed to air. This coat makes it resistant to corrosion. Resistance can be improved by making a layer of oxide thinker. In this technique, the aluminium article is the anode, and the electrolyte is sulphuric acid. The anode reaction results in the formation of a black-coloured film of aluminium oxide on the anode. By putting appropriate dyes in the electrolytic solution, both coloured surface with the decorative finish is achieved. Kitchen articles like anodised such as pressure cookers, pans and frames of sliding windows are applications of this technique. |
- Name the anode and electrolyte used in this technique.
- How can we make aluminium articles made resistant to corrosion?
- Name the technique used to coat the aluminium articles.
