Advertisements
Advertisements
Question
Explain why, iron sheets are coated with zinc.
Advertisements
Solution
Iron sheets are coated with zinc because zinc is a reactive metal which readily reacts with oxygen present in air to form a hard layer of zinc oxide. This layer is so hard that it prevents air and moisture from passing through it. Hence, moist air cannot come in contact with iron. This in turn prevents the rusting of iron.
APPEARS IN
RELATED QUESTIONS
Give two examples of alloys with their chemical composition.
Which of the following methods is suitable for preventing an iron frying pan 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
What is anodising? Give its applications.
Fill in the following blank with suitable word:
The corrosion of iron is called ................
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
Corrosion can be an advantage in some case.Explain ?
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.
Write scientific reasons.
Lemon or tamarind is used for cleaning copper vessels turned greenish.
Which of the following method is used to prevent the accumulation of greenish layer on brass due to corrosion?
Pressure cooker : Anodizing : : Silver plated spoons : _______
Draw a neat labelled diagram.
Anodizing
The process of coating the surface of the metal with a thin layer of zinc is called ______
Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of ____________.
The diagram shows the reaction between metal and dil. acid.
What is the reason for different behaviour of Mg in test tube B?
State whether the following statement is true or false:
Ships suffer a lot of damage though they are painted.
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.
Describe two changes that are harmful. Explain why you consider them harmful. How can you prevent them?
