Precipitation in Double Displacement Reactions

PIERRE COMASCRISTINA RÍOS

Introduction Double Replacement Reactions

A double displacement reaction involves the reaction of two compounds to form two new compounds. In effect, the compounds change partners with each other.

Purpose

• The purposes of this experiment are:• To observe precipitation reactions by

mixing aqueous solutions of cations and anions.

• To write and balance complete chemical equations for precipitation reactions

Purpose

Materials

• The material which we need are following:

• Pb(NO3)2 CaCl2 • KI NaCl • NaOH FeCl3 • Na2CO3 CuSO4 • AgNO3 Test tubes• KNO3 Test tubes rack

• We put 21 clean test tubes in a test tube rack.• We add 6 drops of the solutions indicated which are: KI,• NaCl, NaOH, FeCl3, KNO3, Na2CO3, CuSO4 to 7 clean test tube . • We add 6 drops of AgNO3 solution to every test tube.• We have to observe and record information and colour of any

precipitate formed .• We do the same with Pb(NO3)2 and with CaCl2. • We clean the test tubes and dispose of the wastes in the waste

container.• And finally we write correctly equations for all of the reactions

where a precipitate is formed.

Procedure of these reactions

Reactions with AgNo3 • When we add a small quantity of

Potassium Iodide to Silver Nitrate two compounds are produced Potassium Nitrate and a precipitate of Silver Iodide.

• AgNO3 + KI → KNO3 + AgI↓

• Precipitate has got a Yellow colour.

AgNO3 and NaCl• When we add a small quantity of Sodium

Chloride solution to Silver Nitrate solution it produce Sodium Nitrate and a precipitate of Silver Chloride.

• AgNO3 + NaCl → NaNO3 + AgCl↓

Precipitate has got white colour.

AgNO3 and CuSO4

• Copper nitrate and Silver Sulphate are formed when Silver Nitrate and Copper Sulphate react with each other.

The precipitate is Silver Sulphate.

• AgNO3 + CuSO4 → Cu(NO3)2 + Ag2SO4

• The colour of precipitate is light blue.

AgNO3 and Na2CO3

• Silver Nitrate and Sodium Carbonate react to form Sodium Nitrate and Silver Carbonate. The precipitate is Silver Carbonate.

• AgNO3 + Na2CO3 → Na2CO3 + Ag2CO3↓

• Precipitate’s colour is light Green.

AgNO3 and FeCl3

• Iron Nitrate and Silver Chloride are produced when Silver Nitrate reacts with Iron(III) Chloride.

• AgNO3 + FeCl3 → Fe(NO39 + AgCl3↓

• The precipitate colour was light Yellow.

Reactions with Lead (II) Nitrate

• Potassium nitrate and Lead Iodide• are formed when Lead (II) Nitrate• react with Potassium Iodide . • The precipitation is Lead Iodide.• Pb(NO3)2 + 2KI → 2KNO3 + PbI2

• The precipitation’s colour is Yellow.

Pb(NO3)2 and NaCl

• When Lead (II) Nitrate react with • Sodium Chloride it produced • Sodium Nitrate and • Lead (II) chloride.• Pb(NO3) + 2NaCl →2NaNO3 + PbCl2

• The precipitation has got white colour.

Pb(NO3)2 and KNO3• When Lead (II) Nitrate and • Potassium Nitrate react with • each other it produced • equal products as reactants • because Potassium take• place of Lead and Lead takes• place of Potassium so it produced same.

• Pb(NO3)2 + KNO3 → KNO3 + PbNO3

• The precipitate’s colour • is transparent white.

Pb(NO3)2 and Na2CO3

• When Lead (II) Nitrate and• Sodium Carbonate it • produced Sodium Nitrate• and Lead Carbonate as a precipitate.

• Pb(NO3)2 + Na2CO3 → Na2NO3 + PbCO3

• The precipitate has got White colour.

Pb(NO3)2 and NaOH• Sodium Nitrate and Lead (II) Hydroxide are

formed when Lead (II) Nitrate and Sodium Hydroxide react with each other.

• Pb(NO3)2 + 2NaOH → 2NaNO3 + Pb(OH)2

• The precipitation has got a white colour.

• In all the reactions Silver was a precipitate because Silver is a solid and don’t mix in solution and left in the bottom of the test tube.

• The two cations which form precipitate are Iodine and Chloride.

Conclusion

Remember this one prohibited to drink any of the products that we have used.

Thanks for your attention