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प्रश्न
You are given samples of three metals − sodium, magnesium and copper. Suggest any two activities to arrange them in order of their decreasing reactivities.
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उत्तर
Sodium, magnesium and copper can be arranged based on their reactivity with water. Sodium reacts violently with cold water because it is the most reactive of the three. Magnesium does not react with hot or cold water; it reacts with only steam. Copper does not react even with steam and it is the least reactive of the three.
These three metals can be arranged based on their reactivity with a dilute acid as well. Sodium reacts with dilute hydrochloric acid violently. Magnesium reacts with dilute hydrochloric acid but less rapidly than sodium. Copper is the least reactive and it does not react with dilute hydrochloric acid.
So the order of their decreasing reactivity is sodium > magnesium > copper.
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संबंधित प्रश्न
Iron is
(a) More reactive than zinc
(b) More reactive than aluminium
(c) Less reactive than copper
(d) Less reactive than aluminium
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
| Metal | Iron (II) sulphate | Cooper (II) sulphate | Zinc sulphate | Silver nitrate |
| A | No reaction | Displacement | ||
| B | Displacement | No reaction | ||
| C | No reaction | No reaction | No reaction | Displacement |
| D | No reaction | No reaction | No reaction | No reaction |
Use the Table above to answer the following questions about metals A, B, C and D.
- Which is the most reactive metal?
- What would you observe if B is added to a solution of copper (II) sulphate?
- Arrange the metals A, B, C and D in the order of decreasing reactivity.
Name two metals which form amphoteric oxides.
Name the metal which has been placed at the bottom of the reactivity series.
Which of the following elements would yield an acidic oxide.
Na, S, C, K, H
What happens when a rod of zinc metal is dipped into a solution of copper sulphate? Give chemical equation of the reaction involved.
Which gas is produced when dilute hydrochloric acid is added to a reactive metal?
What is the action of water on sodium ? Write equation of the chemical reaction involved.
Write one reaction in which aluminium oxide behaves as a basic oxide and another in which it behaves as an acidic oxide.
Write the equation for the reaction of Magnesium with dilute hydrochloric acid.
Name the products formed. Also indicate the physical states of all the substances involved.
Write the equation for the reaction of Zinc with dilute hydrochloric acid.
Name the products formed. Also indicate the physical states of all the substances involved.
The least reactive metal among the following is:
(a) sodium
(b) silver
(c) copper
(d) lead
The elements whose oxides can turn litmus solution red are:
(a) lithium and sodium
(b) copper and potassium
(c) carbon and hydrogen
(d) phosphorus and sulphur
An element is soft and can be cut with a knife. If is very reactive and cannot be kept open in the air. It reacts vigorously with water. The element is most likely to be:
(a) Mg
(b) S
(c) P
(d) Na
Name a metal which does not react with cold as well as hot water but reacts with steam.
Calcium floats over water during the reaction with water. Give reason.
Write the chemical equation for the following reaction:
Manganese dioxide is heated with aluminum powder.
A cable manufacturing unit tested few elements on the basisof their physical properties.
| Properties | W | X | Y | Z |
| Malleable | Yes | No | No | Yes |
| Ductile | Yes | No | No | Yes |
| Electrical conductivity | Yes | Yes | Yes | No |
| Melting Point | High | Low | Low | High |
Which of the above elements were dicarded for usage by the company?
Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?
- Good thermal conductivity
- Good electrical conductivity
- Ductility
- High melting point
Why is acidified water considered to be a good conductor of electricity?
