Chapter 4 : Redox Reactions Part 1 SABIS Grade 11 (Level M) Chemistry





Chapter 4 Part 2












4.1 Experiment: An Introduction to Oxidation-Reduction

4.1.1 Reaction between Zinc, Copper and Their Ions
a) Place 3 ml of 0.10 M Zn(NO3)2 in each of two 13 × 100 ml test-tubes.
Place a strip of copper (0.5 cm × 10 cm) in one and a strip of zinc (0.5 cm × 10 cm) in the other.

Figure 4.1 (A) Zinc rod in copper nitrate solution
                 (B) Copper deposite on the zinc rod.

Write your observations in your laboratory copybook.

b) Place 3 ml of 0.10 M Cu(NO3)2 in each of two 13 × 100 ml test-tubes.
Place a strip of copper (0.5 cm × 10 cm) in one and a strip of zinc (0.5 cm × 10 cm) in the other. The blue color of the solution is due to Cu2+(aq).
Write your observations in your laboratory copybook.

4.1 Experiment: An Introduction to Oxidation-Reduction

4.1.2 Reaction between Halogens (Cl₂, Br₂, I₂) and Halide Ions
Color of halogens in carbon tetrachloride
Obtain three 13 × 100 ml test-tubes. Place halogen water to a height of 3 cm in each test tube
(about 3 ml). In the first, place chlorine water (Clorox with dilute HCl), in the second, bromine water and
in the third, iodine dissolved in water and some ethanol (iodine dissolves to a very small extent in pure
water.) Place about 1 ml of carbon tetrachloride, CCl4, in each tube. Fit each test tube with a stopper
and shake. Note the color of the CCl4 in each test tube.

Reactions of halogens with halide ions
a) Place about 3 ml of 0.1 M NaBr in one test tube and about 3 ml of 0.1M NaI in another test tube.
Add about 1 ml of CCl4 to each tube. Add about 2 ml chlorine water to each tube. Shake. Note the
color of the CCl4 layer.
Write a balanced net ionic equation for each reaction.

b) Place about 3 ml of 0.1 M NaCl in one test tube and about 3 ml of 0.1M NaI in another test tube. Add to each tube about 1 ml of CCl4. Add about 1 ml bromine water to each tube. Shake. Note the color of the CCl4 layer.
Write a balanced equation for each reaction.

c) Place about 3 ml of 0.1 M NaCl in one test tube and about 3 ml of 0.1M NaBr in another test tube. Add to each tube about 1 ml of CCl4. Add about 1 ml iodine water to each tube. Shake. Note the color of the CCl4 layer.
Write a balanced equation for each reaction.
Write a generalization about the above reactions (check whether everyone in class got the same results).

Competition for electrons between the halogens
Halogens have each one electron less than a noble gas. They tend to react by gaining one electron:
X + e–→ X–
We have seen that whenever Cl2(aq) is mixed with I–(aq) or Br–(aq), chlorine takes the electron from bromine or iodine ion:
Cl2(aq) + 2Br–(aq) → 2Cl–(aq) + Br2(aq)
Cl2(aq) + 2I–(aq) → 2Cl–(aq) + I2(aq)
Chlorine can displace bromine or iodine from their salts, and bromine can displace iodine from its salt:
Br2(aq) + 2I–(aq) → 2Br–(aq) + I2(aq)



4.1 Experiment: An Introduction to 

Oxidation-Reduction


Write a pure and complete ionic equation for a reaction that occurs in an aqueous medium under 
standard conditions.
Do not include state symbols in your answer and write “NR” if no reaction occurs.
Fill in the form:
Complete ionic equation: Br2 + NaCl →


Write a pure and complete ionic equation for a reaction that occurs in an aqueous medium under
standard conditions.
Do not include state symbols in your answer and write “NR” if no reaction occurs.
Fill in the form:
Complete ionic equation: Br2 + 2KI → I2 +

Write a pure and complete ionic equation for a reaction that occurs in an aqueous medium under
standard conditions.
Do not include state symbols in your answer and write “NR” if no reaction occurs.
Fill in the form:
Complete ionic equation: Cl2  + 2LiBr  → Br2 +


Which halogen can displace bromine or iodine from their salts?

4.1.2 Reaction between Halogens (Cl₂, Br₂, I₂) 

and Halide Ions


Color of halogens in carbon tetrachloride



Obtain three 13 × 100 ml test-tubes. Place halogen water to a height of 
3 cm in each test tube (about 3 ml). In the first, place chlorine water 
(Clorox with dilute HCl), in the second, bromine water and in the third, 
iodine dissolved in water and some ethanol (iodine dissolves to a very small
extent in pure water.) Place about 1 ml of carbon tetrachloride, CCl4, 
in each tube. Fit each test tube with a stopper and shake. Note the color of the CCl4 in each test 
tube.

Reactions of halogens with halide ions
a) Place about 3 ml of 0.1 M NaBr in one test tube and about 3 ml of 0.1M NaI in another test tube. 
Add about 1 ml of CCl4 to each tube. Add about 2 ml chlorine water to each tube. Shake. Note the 
color of the CCl4 layer.
Write a balanced net ionic equation for each reaction.

b) Place about 3 ml of 0.1 M NaCl in one test tube and about 3 ml of 0.1M
 NaI in another test tube. Add to each tube about 1 ml of CCl4. Add about
 1 ml bromine water to each tube. Shake. Note the color of the CCl4 layer.

Write a balanced equation for each reaction.

c) Place about 3 ml of 0.1 M NaCl in one test tube and about 3 ml
 of 0.1M
 NaBr in another test tube. Add to each tube about 1 ml of CCl4. Add about 1 ml iodine water
 to 
each tube. Shake. Note the color of the CCl4 layer.
Write a balanced equation for each reaction.
Write a generalization about the above reactions (check whether everyone in class got the same 
results).

Competition for electrons between the halogens
Halogens have each one electron less than a noble gas. They tend to react by gaining one electron:

X + e–→ X–
We have seen that whenever Cl2(aq) is mixed with I–(aq) or Br–(aq), chlorine takes the electron from 
bromine or iodine ion:
Cl2(aq) + 2Br–(aq) → 2Cl–(aq) + Br2(aq)
Cl2(aq) + 2I–(aq) → 2Cl–(aq) + I2(aq)
Chlorine can displace bromine or iodine from their salts, and bromine can displace iodine from its 
salt:
Br2(aq) + 2I–(aq) → 2Br–(aq) + I2(aq)


Write a pure and complete ionic equation for a reaction that occurs in an aqueous medium under standard conditions.
Do not include state symbols in your answer and write “NR” if no reaction occurs.
Fill in the form:
Complete ionic equation: Br2 + NaCl → 
 Write a pure and complete ionic equation for a reaction that occurs in an aqueous medium under standard conditions.
Do not include state symbols in your answer and write “NR” if no reaction occurs.
Fill in the form:
Complete ionic equation: Br2 + 2KI → I2 + 
Write a pure and complete ionic equation for a reaction that occurs in an aqueous medium under standard conditions.
Do not include state symbols in your answer and write “NR” if no reaction occurs.
Fill in the form:
Complete ionic equation: Cl2  + 2LiBr  → Br2 +

Which halogen can displace bromine or iodine from their salts?

Part 2