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Question
What do you mean by a precipitation reaction? Explain by giving examples.
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Solution
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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RELATED QUESTIONS
Complete the following reaction, balance it and write the name of the products CuO + HCI →_________ + _________
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.
What type of chemical reaction is represented by the following equation?
PQ + RS → PS + RQ
What is meant by double displacement reaction? Explain with help of one example.
What happens when silver nitrate solution is added to sodium chloride solution?
Name the type of reaction involved.
(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.
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(b) What is the colour of salt XSO4?
(c) Name the black precipitate XS.
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(e) What type of chemical reaction takes place in this case?
The aqueous solutions of copper sulphate and zinc sulphate appear
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(B) green and colourless respectively
(C) blue and brown respectively
(D) blue and colourless respectively.
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(ii) What type of reaction is this?
(iii) Write a balanced chemical equation to represent the above reaction.
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:
Which of the following represents a precipitation 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
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.
