Yeh, they both look exactly the same, just some small differences:
Dry Cell Anode Reaction: Zn(s) --> Zn^(2+) + 2e^(-) (Zinc casing is Anode)
Alkaline Anode Reaction: Zn + 2OH^(-) --> Zn(OH)2 + 2e^(-) (Powdered Zinc around the central Steel/brass electrode form the anode)
Dry Cell Cathode Reaction: MnO2 + NH4 ^(+) + H2O + e^(-) --> Mn(OH)3 + NH3 (Central carbon rod surrounded by powdered carbon + Manganese Dioxide form the cathode)
Alkaline Cathode Reaction: MnO2 + 2H2O + e^(-) --> Mn(OH)3 + OH^(-) (Outer steel casing + manganese dioxide + powdered carbon form cathode)
Dry Cell Electrolyte: Ammonium Chloride Paste
Alkaline Electrolyte: Potassium Hydroxide Paste
Dry Cell Voltage: Delivers 1.5 when new but decreases once used
Alkaline Voltage: Delivers higher current for longer
Electrolyte: Less electrolyte needed in Alkaline than Dry so there is more room for reactants in the Alkaline
Cost: Dry cell is cheaper per battery than alkaline, but since Alk. lasts longer the cost per unit of electricity is comparable
Dangers/Environmental impact: Dry Cell has little impact on the environment, but as it discharges, the Zinc case is eaten away and it can leak. Alkaline cell also has little impact on the environment, but doesn't have it's case eaten away and it rarely leaks.
So, they are different and you don't have to use the Dry Cell, you can use the alkaline. Hope this helps.
