Hey there! We receieved your request
Stay Tuned as we are going to contact you within 1 Hour
One of our academic counsellors will contact you within 1 working day.
Click to Chat
1800-5470-145
+91 7353221155
Use Coupon: CART20 and get 20% off on all online Study Material
Complete Your Registration (Step 2 of 2 )
Sit and relax as our customer representative will contact you within 1 business day
OTP to be sent to Change
Dear student,
In the most common type of dry cell battery, the cathode is composed of a form of elemental carbon called graphite, which serves as a solid support for the reduction half-reaction. In an acidic dry cell, the reduction reaction occurs within the moist paste comprised of ammonium chloride (NH4Cl) and manganese dioxide (MnO2):
2 NH4+ + 2 MnO2 + 2e- ------> Mn2O3 + 2 NH3 + H2O
A thin zinc cylinder serves as the anode and it undergoes oxidation:
Zn (s) ---------------> Zn+2 + 2e-
This dry cell "couple" produces about 1.5 volts. ( These "dry cells" can also be linked in series to boost the voltage produced). In the alkaline version or "alkaline battery", the ammonium chloride is replaced by KOH or NaOH and the half-cell reactions are:
Zn + 2 OH- -------> ZnO + H2O + 2e- 2 MnO2 + 2e- + H2O -------> Mn2O3 + 2 OH-
The alkaline dry cell lasts much longer as the zinc anode corrodes less rapidly under basic conditons than under acidic conditions.
Other types of dry cell batteries are the silver battery in which silver metal serves as an inert cathode to support the reduction of silver oxide (Ag2O) and the oxidation of zinc (anode) in a basic medium. The type of battery commonly used for calculators is the mercury cell. In this type of battery, HgO serves as the oxidizing agent (cathode) in a basic medium, while zinc metal serves as the anode. Another type of battery is the nickel/cadmium battery, in which cadmium metal serves as the anode and nickel oxide serves as the cathode in an alkaline medium. Unlike the other types of dry cells described above, the nickel/cadmium cell can be recharged like the lead-acid battery.
Get your questions answered by the expert for free
You will get reply from our expert in sometime.
We will notify you when Our expert answers your question. To View your Question
Win Gift vouchers upto Rs 500/-
Register Yourself for a FREE Demo Class by Top IITians & Medical Experts Today !