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Electrical conductivity

Syllabus HAVO: Bonding and properties

Question 1 / 50 correct

Why does a sugar solution conduct much less well than a salt solution?

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Charge must be able to move

In solid sodium chloride, charged ions occupy fixed positions in a lattice. When melted or dissolved, the ions can move. The presence of ions alone is therefore not enough.

Metals are different

Mobile electrons carry charge in copper. In a sugar solution the dissolved particles are neutral molecules. In this classroom model its conduction is negligible compared with a salt solution.

Why does molten NaCl conduct whereas solid NaCl does not?

  1. Both contain Na⁺ and Cl⁻ ions.
  2. In the solid they occupy fixed lattice positions; in the melt they can move.
In the melt, ions transport electric charge.
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