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.
What are amphoteric oxides?
Diamond : electric insulator : : _______ : electric conductor
Example of an amphoteric oxide is:
Which of the following metals liberate hydrogen with 5% HNO3?
(i) Cu
(ii) Zn
(iii) Mn
(iv) Mg
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)?
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?
Zinc sulphate forms a colourless solution in water. Will you observe any colour on adding copper turning in it?
Answer the questions based on the figure below:
- Which experiment setup is demonstrated in the figure?
- What do you conclude after the reactions? Name reaction.
Answer the questions based on the figure below:
- Which reaction is shown in the figure?
- Which gas is evolved in the reaction?
- Give an example of reactants that rapidly show this reaction. Give equations.
- Give an example of reactants that do not react rapidly.
- In what condition will reactants of (c) part react? Give equation.
Metal oxides generally react with acids, but few oxides of metal also react with bases. Such metallic oxides are:
- MgO
- ZnO
- Al2O3
- Cao
Select the appropriate state symbols of the products given as X and Y in the following chemical equation by choosing the correct option from table given below:
\[\ce{Zn_{(s)} + H_2SO_{4(l)} ->ZnSO_{4(X)} + H_{2(Y)}}\]
Write a chemical equation showing the ionic products formed on dissolving potassium hydroxide in water.
