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सी.आई.एस.सी.ई.आईसीएसई ICSE Class 8

Define Precipitation . - Chemistry

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प्रश्न

Define precipitation.

परिभाषा
एक पंक्ति में उत्तर

उत्तर

 Precipitation: A chemical reaction in which two compounds in their aqueous state react to form an insoluble salt as one of the product.
Acid + Base → Salt + Water
Example.
\[\ce{\underset{\text{Barium chloride}}{BaCl2 (aq)} + \underset{\text{Sodium sulphate}}{Na2SO4 (aq)} -> \underset{\text{Barium sulphate white ppt}}{BaSO4^-}+ \underset{\text{sodium chloride}}{2NaCl (aq)}}\]

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अध्याय 6: Chemical Reactions - Exercise 2 [पृष्ठ ८६]

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सेलिना Concise Chemistry [English] Class 8 ICSE
अध्याय 6 Chemical Reactions
Exercise 2 | Q 3.1 | पृष्ठ ८६

संबंधित प्रश्न

Define; catalyst.


MULTIPLE CHOICE QUESTIONS

Tick the most appropriate answer.

Compounds, which in their molten state allow an electric current to pass through them are called

  1. electrolytes
  2. non-electrolytes
  3. non-conductors
  4. none of these

FILL IN THE BLANK

On reaction with sulphuric acid solution, barium chloride forms a white precipitate of ........ sulphate.


TRUE \ FALSE

A precipitation reaction takes place only in a solution.


TRUE \ FALSE

Electrolytic refining is a method in which a thin coating of a metal is done over another metal.


What are biocatalysts ?


What are homogenous reactions ?


What do you observe when :

an iron nail is kept in tap water for few days


 Fill in the blank

A new substance is formed in a _______ change.


State four conditions necessary for a chemical reaction to take place.


Name the type of chemical reaction shown by the following equation:

2Mg + O2 → 2MgO


Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.


Out of sodium and sulphur which is a metal? Explain its reaction with the oxygen.


Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.

(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)

A colourless solution of calcium hydroxide in a test tube turns ______ on blowing in it through a blow tube for some time.


Give an example of a reaction where the following are involved:

Solution


What do you observe? When

Sodium chloride solution is added to silver nitrate solution.


Complete the following table and write your observations.

 

Hydrogen sulphide

Ammonia

Sulphur dioxide

Hydrogen chloride

Shake the gas with red litmus solution

       

Shake the gas with blue litmus solution

       

Apply a burning splint to a gas

       

Write your observation and a balanced equation in the case of the following substances being heated.

Ammonium chloride 


Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.


Give reason for the following:

A characteristic change of colour is seen when a piece of iron is added to copper [II] sulphate solution.


State whether the following reaction is oxidation or reduction.

\[\ce{Na->Na+}\]


Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to sodium sulphite.


Chemical change is a temporary change.


State whether the following statements are true or false:

When a candle burns, both physical and chemical changes take place.


Give an example of a chemical reaction for each of the following situations:

A change in colour is observed.


Heat may evolve or be absorbed during a ______ change.


Write the chemical reaction of baking soda with lemon.


When carbon dioxide is passed through lime water ______.


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