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प्रश्न
Explain the following reaction with the balanced equation.
Dry aluminium hydroxide is ignited at 1000 °C
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उत्तर
When dry aluminium hydroxide is calcined by at 1000 °C, pure aluminium oxide, called alumina is obtained.
\[\ce{\underset{\text{Aluminium hydroxide}}{2Al(OH)_{3(s)}} ->[heat][1000 °C] \underset{\text{Aluminium oxide}}{Al2O_{3(s)}} + \underset{\text{Water vapour}}{3H2O_{(g)}}}\]
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संबंधित प्रश्न
Name the gas in air which tarnishes silver articles slowly.
Which one of the methods given in column I is applied for the extraction of each of the metals given in column II:
| Column I | Column II |
| Electrolytic reduction | Aluminium |
| Reduction with Carbon | Zinc |
| Reduction with Aluminium | Sodium |
| Iron | |
| Manganese | |
| Tin |
Why does aluminium not corrode right through?
How is zinc extracted from its carbonate ore (calamine)? Explain with equations.
A zinc ore on heating in air forms sulphur dioxide. Describe briefly any two stages involved in the conversion of this concentrated ore into zinc metal.
Explain giving equation, what happens when:
ZnCO3 is heated in the absence of air?
What is the difference between a mineral and an ore?
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
Which of the following is an iron ore?
When an object made of metal A is kept in air for a considerable time, it loses its shine and becomes almost black due to the formation of a layer of substance B. When an object made of another metal C is kept in damp air for a considerable time, it gets covered with a green layer of substance D. Metal A is the best conductor of electricity whereas metal C is the next best conductor of electricity.
- What is metal А?
- What is metal C?
- Name the substance B.
- Name the substance D.
- What type of chemical can be used to remove the green layer from metal C and clean it? Why?
Which metal can be extracted from the following ore?
Calamine
Name the following:
Two metals which are found in the free or native state.
Name the following:
The process of heating a substance very strongly in such a way that it does not combine with oxygen.
How an ore is concentrated by froth floatation process?
State the property of the metal being utilized in the following :
| Use of metal | Property |
| Zinc in Galvanization | |
| Aluminium in Thermite welding |
Sulphide ores : Roasting : : Carbonate ores : _______
Explain concept with example/explain with the help of a balanced equation.
Roasting
Read the following passage and answer the questions.
According to the reactivity series, zinc is more reactive than iron, iron is more reactive than silver. During study of this, a student dipped the iron nails in silver nitrate solution.
- What is reactivity series?
- What will happen when iron nails are dipped in silver nitrate solution?
- Which type of reaction happens when iron metal reacts with silver nitrate solution?
- What will happen if a zinc rod is used instead of iron nail?
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- Given below are the steps for extraction of copper from its ore. Write the reaction involved.
- Roasting of copper (I) sulphide
- Reduction of copper (I) oxide with copper (I) sulphide.
- Electrolytic refining
- Draw a neat and well labelled diagram for electrolytic refining of copper
