Final answer:
Leclanché dry cells have disadvantages including a short lifespan, inefficiency in chemical usage, the potential for leakage, and the fact that they cannot be recharged.
Step-by-step explanation:
The Leclanché dry cell, despite its common use and manufacturing in vast numbers, does have several notable disadvantages. One major drawback is that it has a relatively short lifespan. This is due in part to the inefficiency in its chemical reactions; only a small fraction of the MnO₂ that is near the cathode is reduced during discharge, and similarly, only a small fraction of the zinc anode is consumed. Another disadvantage is that dry cells are not rechargeable, making them primary batteries that can only be used once. A third issue is the spontaneous reaction of the Zn anode with NH₄Cl in the electrolyte, which can lead to corrosion of the case and leakage of battery contents. Furthermore, the acidic components in the electrolyte can cause leakage problems, as depicted in Figure 8.3.2, which shows a dry cell with a leak. In summary, the limitations of the dry Leclanché cell include a short, non-rechargeable lifespan, inefficiencies in chemical usage, potential for leakage, and inability to be recharged.