Final answer:
The electrolysis method for desalination is correctly described as 'c. Electric current to separate ions'. Electrolysis uses electrical energy to cause chemical reactions that separate ions in saltwater to produce purified water.
Step-by-step explanation:
The correct description for the electrolysis method for desalination is c. Electric current to separate ions. Electrolysis is a process that uses electrical energy to drive chemical reactions that otherwise would not occur on their own. In the context of desalination, electrolysis involves applying an electric current to separate charged particles (ions) such as sodium and chloride, which are found in saltwater, thereby removing the salt and purifying the water.
Reverse osmosis, on the other hand, involves using pressure to force water through a semipermeable membrane, which allows water to pass but blocks the larger ions and molecules, resulting in desalinated water. This technique is distinct from electrolysis and is not the correct answer to the question. Distillation and chemical precipitation also do not utilize electric current to separate ions and are therefore not matching descriptions for the electrolysis method.