Group 7 QP

Question 1

How do weak intermolecular forces arise between chlorine? [3]

Answer 1

[1] Random movement of electrons in one molecule

[2] Induces a temporary molecule in the neighbouring molecule

[3] Temporary dipoles attract

Question 2

What is the equation between chlorine and water? [1]

Answer 2

[1] Cl2 + 2H2O –> HCl + HClO

Question 3

Equation for the manufacturing of bleach? [1]

Answer 3

[1] Cl2 + 2NaOH –> NaClO + NaCl

Question 4

Why is excess of silver nitrate used in practicals? [1]

Answer 4

[1] To ensure all halide ions are removed

Question 5

State an observation when sodium chlorine reacts with concentrated sulfuric acid? What is the equation? What is the role of the chlorine ions? [3]

Answer 5

[1] Misty fumes

[2] H2SO4 + NaCl –> NaHSO4 + HCl

[3] Base

Question 6

Give the equation for the redox reaction between solid sodium bromide and concentrated sulfuric acid? Why is it redox? [3]

Answer 6

[1] 2NaBr + 2H2SO4 –> Na2SO4 + Br2 + SO2 + 2H20

[2] Br changes oxidation state from −1 to 0 and is oxidised

[3] S changes oxidation state from +6 to +4 and is reduced

Question 7

What is observed when aqueous chlorine is added to sodium bromide solution? What is the ionic equation? [2]

Answer 7

[1] Orange solution

[2] Cl2 + 2Br- –> 2Cl- + Br2

Question 8

What is the role of sulfuric acid when reacting with group 7? [1]

Answer 8

[1] Proton donor

Question 9

What is the equation, an observation and role of sulfuric acid when sodium bromide reacts with conc sulfuric acid? [3]

Answer 9

[1] 2NaBr + 2H2SO4 + SO2 + Br2 + 2H20

[2] Orange fumes

[3] Oxidisng agent