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प्रश्न
Complete and balance the following equation:
Na + O2 →
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उत्तर
4Na(s) + O2(g) → 2Na2O(s)
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संबंधित प्रश्न
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.
What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place.
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be:
A solution of _________________ in water is green in colour.
(a) CuSO4
(b) FeSO4
(c) ZnSO4
(d) Al2(SO4)3
Explain the following reaction with the help of a balanced chemical equation:
Magnesium reacts with hot water.
Complete and balance the following equation:
Na2O + H2O →
Describe the reaction of potassium with water. Write the equation of the reaction involved.
What happens when a metal reacts with dilute hydrochloric acid? Explain with the help of an example.
Out of the following oxides, the amphoteric oxide is:
(a) Fe2O3
(b) Al2O3
(c) P2O5
(d) N2O
An element X forms two oxides XO and XO2. The oxide XO is neutral but XO2 is acidic in nature. The element X is most likely to be:
(a) sulphur
(b) carbon
(c) calcium
(d) hydrogen
A metal less reactive and another metal more reactive than hydrogen are:
(a) aluminium and lead
(b) iron and magnesium
(c) copper and tin
(d) copper and mercury
An element E reacts with water to form a solution which turns phenolphthalein solution pink. The element E is most likely to be:
(a) S
(b) Ca
(c) C
(d) Ag
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
An element X forms two oxides XO and XO2. The oxide XO has no action on litmus solution but oxide XO2 turns litmus solution red.
(a) What is the nature of oxide XO?
(b) What is the nature of oxide XO2?
(c) Would you call element X a metal or a non-metal? Give reason for your choice.
(d) Can you give an example of element like X?
Write the name and formula of a molecule made up of three atoms of oxygen.
Where does the metal aluminium, used in the thermit process, occurs in the reactivity series of metals?
Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?
Tungsten wire is used in electric bulbs.
