Q.5. Collect information of pollution free battery.

Step 1. Among the electrochemical power sources covered in this chapter, the hydrogen-oxygen fuel cell (section 5.11.1) stands out as essentially pollution-free: its overall reaction is simply $2H_2(g)+O_2(g)\rightarrow2H_2O(l)$, so its only byproduct is water, unlike batteries containing heavy metals such as lead, mercury, cadmium or nickel.

Step 2. Because a fuel cell's reactants are continuously supplied rather than stored and discarded, it also avoids generating the solid chemical waste that a spent primary (non-rechargeable) dry cell produces. …

Connect this open research prompt to the H2-O2 fuel cell already covered in the chapter (its only product is water) plus general standa …

• Citing specific brand names, market statistics or performance figures not grounded in the textbook or in safely-general chemistry knowledge …