What would happen with non-electrolytes?
2 marks · EasyA student tests solid sodium chloride and sugar for electrical conductivity. She finds that only molten sodium chloride conducts electricity, while sugar does not conduct electricity when molten or in solution.
State, with a reason, whether each substance is ionic, covalent, or a non-electrolyte.
Sodium chloride:
Sugar:
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(a) Ionic; because molten sodium chloride conducts electricity, it contains ions that can move. · must show Identifies sodium chloride as ionic, Links conductivity in molten state to presence of ions
(b) Non-electrolyte (covalent); because sugar does not conduct electricity when molten or in solution, it does not produce ions. · must show Identifies sugar as non-electrolyte or covalent, Links lack of conductivity to no ions present
Common mistakes: Assuming sugar is ionic; Not giving a reason
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Identifies sodium chloride as ionic and gives a valid reason (e.g. conducts electricity when molten; contains ions).
M2 (b) · 1 mark · Identifies sugar as non-electrolyte or covalent and gives a valid reason (e.g. does not conduct electricity; does not produce ions).
Worked solution
a) Sodium chloride is ionic because it conducts electricity when molten. This means it has ions that can move and carry charge.
b) Sugar is a non-electrolyte (covalent) because it does not conduct electricity when molten or in solution, showing that it does not produce ions.