Which statement about electrolyte is correct according to both technicians?

The statement that electrolyte contains water and hydrochloric acid is correct because in the context of automotive batteries, especially lead-acid batteries, the electrolyte is typically a diluted sulfuric acid solution, which is a vital component for the battery's operation. In some other cases, an electrolyte can contain different acids depending on the type of battery, such as hydrochloric acid in certain specialized applications. The key point here is that electrolytes play a crucial role in facilitating the chemical reactions that occur within batteries, which are essential for generating electrical energy.

Other options do not accurately describe the properties of electrolytes in general or in a typical battery setting. For example, many electrolytes are indeed corrosive, especially in the case of batteries containing strong acids, which could cause harm to skin and materials. Hence, understanding the nature of the electrolyte is essential for safe handling and effective diagnostics in automotive applications.