Advertisements
Advertisements
प्रश्न
Give reason:
Sodium, potassium and lithium are stored under oil.
Advertisements
उत्तर
- All three metals react with water, producing a lot of heat. As a result, hydrogen evolves and catches fire.
- They cannot be kept in the air because air contains moisture or water vapours. They are kept under kerosene to avoid contact with both air and water.
संबंधित प्रश्न
Give two examples of amphoteric oxides.
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Diamond : electric insulator : : _______ : electric conductor
Which of the following oxide(s) of iron would be obtained on the prolonged reaction of iron with steam?
Example of an amphoteric oxide is:
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)?
Silver articles become black on prolonged exposure to air. This is due to the formation of
Stainless steel is very useful material for our life. In stainless steel, iron is mixed with
If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of
When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.
Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?
Which of the following reacts with cold water vigorously?
The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is ______.
Zinc sulphate forms a colourless solution in water. Will you observe any colour on adding copper turning in it?
Out of three metals, sodium, calcium and aluminium, which metal reacts most with water? Give the equation of reaction with all three metals.
Keerti added dilute Hydrochloric acid to four metals and recorded her observations as shown in the table given below:
| Metal | Gas Evolved |
| Copper | Yes |
| Iron | Yes |
| Magnesium | No |
| Zinc | Yes |
Select the correct observation(s) and give chemical equation(s) of the reaction involved.
Metal oxides generally react with acids, but few oxides of metal also react with bases. Such metallic oxides are:
- MgO
- ZnO
- Al2O3
- Cao
Write a chemical equation showing the ionic products formed on dissolving potassium hydroxide in water.
On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is produced when a burning match stick is brought near it. Which of the following correctly represents the metal ‘X’?
