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why lead storage battery supllies constant emf.

why lead storage battery supllies constant emf.
 
 

Grade:12

5 Answers

Suraj Prasad IIT Patna
askIITians Faculty 286 Points
9 years ago
Batteries convert chemical energy directly to electrical energy. A battery consists of some number of voltaic cells. Each cell consists of two half-cells connected in series by a conductive electrolyte containing anions and cations. One half-cell includes electrolyte and the negative electrode, the electrode to which anions (negatively charged ions) migrate; the other half-cell includes electrolyte and the positive electrode to which cations (positively charged ions) migrate. Redox reactions power the battery. Cations are reduced (electrons are added) at the cathode during charging, while anions are oxidized (electrons are removed) at the anode during discharge. The electrodes do not touch each other, but are electrically connected by the electrolyte. Some cells use different electrolytes for each half-cell. A separator allows ions to flow between half-cells, but prevents mixing of the electrolytes.

rohan
12 Points
9 years ago
i dont get it i asked how can they supply constant emf when there is solution and concentration nerst equation must be valid so the emf must change with time
Suraj Prasad IIT Patna
askIITians Faculty 286 Points
9 years ago
see emf is constantly maintaned because there is continuous supply of electrons from the redox reaction going inside the cell. i hope you got it now in simple words...
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rohan
12 Points
9 years ago
i mean the flow of electrons depends upon the concentration involved according to nerst equation.
the batteries used in home are lead storage, they supply constant emf 220V but the concentration changes with time so should the emf but that doesnt happens.
Suraj Prasad IIT Patna
askIITians Faculty 286 Points
9 years ago
look, let me make it very clear now...the electrode used is not such that it will get finish for only one reaction.... its conc. is maintained as such the electrons which is flowing will be made constant. , in batteries used in home if u have seen sometime you add sulphuric acid , so that reaction b/w Pb and H2SO4 continues... i hope you got it now

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