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प्रश्न
What do you mean by a precipitation reaction? Explain by giving examples.
उत्तर
When two solutions containing soluble salts are combined, a double displacement reaction takes place in which the ions are exchanged between the compounds. When one such compound is in solid form (that is insoluble in aqua), then it settles down at the bottom of the container. This solid is known as the precipitate and the respective reaction is termed as the precipitation reaction. A few examples of precipitation reactions are:
- \[\ce{CdSO4(aq) + K2S(aq) -> CdS(s) + K2SO4(aq)}\]
- \[\ce{2NaOH(aq) + MgCl2(aq) -> 2NaCl(aq) + Mg(OH)2(s)}\]
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संबंधित प्रश्न
Give an example of a double displacement reaction other than the one given in the following Activity.
•Take about 3 mL of sodium sulphate
solution in a test tube.
• In another test tube, take about 3 mL of
barium chloride solution.
• Mix the two solutions given in the following fig.
• What do you observe?
What is the difference between displacement and double displacement reactions? Write equations for these reactions.
Give two characteristics of the chemical reaction which occurs on adding potassium iodide solution to lead nitrate solution.
What is meant by double displacement reaction? Explain with help of one example.
(a) What happens when an aqueous solution of sodium sulphate reacts with an aqueous solution of barium chloride?
(b) Write the balanced chemical equation for the reaction which takes place.
(c) State the physical conditions of reactants in which the reaction will not take place.
(d) Name the type of chemical reaction which occurs.
(e) Give one example of another reaction which is of the same type as the above reaction.
A red-brown metal X forms a salt XSO4. When hydrogen sulphide gas is passed through an aqueous solution of XSO4, then a black precipitate of XS is formed alongwith sulphuric acid solution.
(a) What could the salt XSO4 be?
(b) What is the colour of salt XSO4?
(c) Name the black precipitate XS.
(d) By using the formula of the salt obtained in (a) above, write an equation of the reaction which takes place when hydrogen sulphide gas is passed through its aqueous solution.
(e) What type of chemical reaction takes place in this case?
Fill in the blank
In the type of reaction called ....................................., ions two compounds exchange their positive and negative radicals ions respectively.
Explain the following type of chemical reaction, giving two examples for it:
Double displacement reaction
Choose the correct option from given alternative:
When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of a:
When a potassium iodide solution is added to a solution of lead (II) nitrate in a test tube, a precipitate is formed.
List two types of reactions in which this reaction can be placed.
Which option denotes a double displacement reaction?
Which among the following is (are) double displacement reaction(s)?
(i) \[\ce{Pb + CuCl -> PbCl2 + Cu}\]
(ii) \[\ce{Na2SO4 + BaCl2 -> BaSO4 + 2NaCl}\]
(iii) \[\ce{C + O2 -> CO2}\]
(iv) \[\ce{CH4 + 2O2 -> CO2 + 2H2O}\]
Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of reaction involved?
(i) Displacement reaction
(ii) Precipitation reaction
(iii) Combination reaction
(iv) Double displacement reaction
In a double displacement reaction ______.
Add potassium chromate (K2CrO4) into the solution of barium sulphate (BaSO4).
- What was the colour of the precipitate formed? Also, write the name of the precipitate.
- Write down the balanced equation for this reaction.
- Will you call this reaction a displacement reaction or a double displacement reaction? Why?
Identify the product which represents the solid state in the above reaction.
Write balanced chemical equation for the following word equation.
Lead nitrate + Potassium iodide → Lead iodide + Potassium nitrate
Is this a double displacement reaction? Justify your answer. Name the compound precipitated and write the ions present in it.
Give an example of a double displacement reaction.
