This question is about some elements in Group 7 and their compounds - AQA - A-Level Chemistry - Question 6 - 2022 - Paper 1
Question 6
This question is about some elements in Group 7 and their compounds.
Chlorine is added to some drinking water supplies to decrease the risk of people suffering from... show full transcript
Worked Solution & Example Answer:This question is about some elements in Group 7 and their compounds - AQA - A-Level Chemistry - Question 6 - 2022 - Paper 1
Step 1
State why the amount of chlorine added must be controlled.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The amount of chlorine must be controlled because excessive chlorine can be toxic and pose health risks to consumers.
Step 2
Give an equation for the reaction of chlorine with water to form a solution containing two acids.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The equation is:
Cl2+H2O→HCl+HClO
Step 3
Explain, with reference to electrons, why this is a redox reaction.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
This is a redox reaction because chlorine (Cl2) is reduced as it gains electrons to form chloride ions (Cl−) and oxidized since it forms hypochlorous acid (HClO) by losing electrons.
Step 4
State the observation the student would make.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The student would observe a brown solution or black solid forming.
Step 5
Give an ionic equation for the reaction.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The ionic equation is:
Cl2+2I−→2Cl−+I2
Step 6
State the role of sulfuric acid in the formation of these products.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Sulfuric acid acts as an oxidizing agent, facilitating the formation of gaseous products by providing the necessary protons.
Step 7
Deduce the identity of the sodium halide.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The identity of the sodium halide is likely sodium iodide (NaI).
Step 8
Suggest the identity of the gas.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The identity of the gas is chlorine (Cl2).
Step 9
Explain the reason for the formation of this gas from the impurity.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The gas forms as a result of the reaction between chlorine and iodide ions, leading to the release of iodine gas and chlorine gas as a byproduct.
Step 10
Use your understanding of the electron pair repulsion theory to draw the shape of this ion.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The shape of the ClF2- ion can be represented as a bent or V-shape due to two lone pairs of electrons on the central chlorine atom repelling the bonding pairs.
Step 11
Explain why the ion has the shape you have drawn.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The shape is due to the repulsion between the lone pairs, which compels the bonding pairs to be as far apart as possible, resulting in a bent structure.
Step 12
Suggest a value for the bond angle in the ion.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The bond angle in the ion is approximately 120 degrees.
Step 13
Give an equation for this reaction.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The equation for the reaction is:
2Mg+TiCl4→2MgCl2+Ti
