What is the electrolyte commonly found in an ordinary storage battery?

The electrolyte commonly found in an ordinary storage battery is sulfuric acid. In lead-acid batteries, which are a common type of storage battery, sulfuric acid serves as the electrolyte fluid that facilitates the electrochemical reaction necessary for generating electrical power. When the battery is charged, lead dioxide (PbO2) and sponge lead (Pb) react with the sulfuric acid (H2SO4) solution to produce lead sulfate (PbSO4) and water (H2O), releasing energy in the process.

This specific chemical composition is crucial because it determines the battery's voltage and storage capacity, making sulfuric acid essential in providing reliable performance in various applications, such as automotive and uninterruptible power supply systems. Other options, while they may serve as electrolytes in different contexts, do not fit the primary role in conventional storage batteries.