This question is about sodium chloride and iodine - AQA - GCSE Chemistry - Question 6 - 2015 - Paper 2
Question 6
This question is about sodium chloride and iodine.
(a) Describe the structure and bonding in sodium chloride.
(b) When sodium chloride solution is electrolysed, on... show full transcript
Worked Solution & Example Answer:This question is about sodium chloride and iodine - AQA - GCSE Chemistry - Question 6 - 2015 - Paper 2
Step 1
Describe the structure and bonding in sodium chloride.
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
Sodium chloride has a crystalline lattice structure, which consists of a regular arrangement of alternating sodium (Na⁺) and chloride (Cl⁻) ions. The ions are held together by strong electrostatic forces of attraction, also known as ionic bonds. This structure allows each sodium ion to be surrounded by six chloride ions, and vice versa, contributing to the stability of the compound.
Step 2
Name the two other products from the electrolysis of sodium chloride solution.
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 two other products from the electrolysis of sodium chloride solution are hydrogen gas (H₂) and sodium hydroxide (NaOH).
Step 3
Give one ethical reason why a compound of iodine should not be added to sodium chloride used in food.
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
One ethical reason is that individuals have the right to choose what they consume; some people may have allergies or adverse reactions to iodine.
Step 4
Complete Figure 4 to show the bonding in iodine (Show the outer electrons only).
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
In Figure 4, iodine can be represented by two iodine atoms each with six outer electrons, with a shared pair of electrons indicating a covalent bond. This results in a simple diatomic molecule (I₂).
Step 5
Explain why iodine has a low melting point.
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
Iodine has a low melting point because it exists as simple molecular structures. The intermolecular forces between iodine molecules are weak van der Waals forces, requiring only a small amount of energy to overcome during melting.
Step 6
Explain, in terms of particles, why liquid iodine does not conduct electricity.
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
Liquid iodine does not conduct electricity because it has no free, mobile electrons or ions that can carry charge. The molecules do not disassociate into charged particles in the liquid state.
