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प्रश्न
A small piece of calcium metal is put into a small trough containing water. There is effervescence and white turbidity is formed.
Write an equation for the reaction.
उत्तर
Ca + 2H2O → Ca(OH)2 + H2
The solution turns blue.
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संबंधित प्रश्न
From the knowledge of activity series, name a metal which shows the following properties:
It displaces hydrogen from dilute HCl.
Hydrogen can be prepared with the metal zinc by using:
acid
Give an equation.
Give an equation to express the reaction between:
Steam and red hot iron
Thin strips of magnesium, copper, and iron are taken.
Write down what happens when these metals are treated as follows:
- Heated in presence of air
- Heated with dil.HCl
- Added to an aqueous solution of zinc sulphate.
Hydrogen is obtained by displacement from:
- dilute sulphuric acid
- dilute hydrochloric acid
Write equations using zinc and iron.
Why does copper not show similar behavior?
When hydrogen is passed over a black solid compound A, the products are a 'colorless liquid' and a 'reddish-brown metal B'.
Substance B is divided into two parts each placed in separate test tubes.
Dilute HCl is added to one part of substance B and dilute HNO3 to the other.
- Name the substances A and B.
- Give two tests for the colourless liquid formed in the experiment.
- What happens to substance A when it reacts with hydrogen? Give reasons for your answer.
- Write an equation for the reaction between hydrogen and substance A.
- Is there any reaction between substance B and dilute hydrochloric acid? Give reasons for your answer.
Choose terms from the options given in brackets to complete this sentence.
Sodium ………………. reacts smoothly with cold water.
(metal, amalgam, in the molten state)
Using dilute sulphuric acid how would you differentiate between:
Sodium sulphide and sodium carbonate.
How would you identify the gaseous products evolved.
State why hydrogen is not prepared in the laboratory by the action of calcium with dilute sulphuric acid.
State why hydrogen is not prepared in the laboratory by the action of lead with dilute hydrochloric acid.
