Final answer:
A dry cell is called 'dry' because its electrolyte is a moist paste rather than a liquid, which makes it less messy and reduces leakage. Dry cells are primary batteries, single-use and with a typical voltage of about 1.56 V. The common Leclanché dry cell has been used extensively despite the somewhat misleading term, as it does contain some moisture within the electrolyte.
Step-by-step explanation:
A dry cell is called a dry cell because the electrolyte within is a moist paste, not a free-flowing liquid. This design minimizes the risk of leakage and makes the battery less messy to handle, hence the name "dry." Despite its name, it's a bit of a misnomer as there is still moisture present within the electrolyte paste. The most common dry cell is the Leclanché cell, which was invented in 1866 and contains a paste of manganese(IV) oxide, ammonium chloride, zinc chloride, graphite, and starch.
Dry cells are primary batteries, meaning they are single-use and cannot be recharged once depleted. With a voltage of about 1.56 V, they are commonly used in a variety of devices such as flashlights and portable electronics, but they have a relatively short lifetime compared to rechargeable alternatives. The outer zinc casing of the dry cell functions as the anode, while the central carbon rod acts as the cathode.
An example of a newer dry cell technology is the alkaline battery, invented by Lewis Urry in the late 1950s. Alkaline batteries use a basic moist paste rather than an acidic one, generally providing a longer lifespan and better performance under load compared to traditional zinc-carbon dry cells.