How does carbon-zinc dry battery work?

Can someone explain in simple terms how carbon-zinc dry battery works and was in the past to expensive to supply households of dry batteries in oppose to mains supply?

Re: dry battery

For your second part, in the past many houses did not have mains power or the mains was DC. Batteries were the only available way to power electronic equipment.

Re: dry battery

Cutting story short, the dry cell "generates" energy by converting metallic zync to zinc ions. Chemically, this is equivalent of burning zinc.
To deliver 1A of current, the dry cell "consumes" ≈1.2g of zinc in one hour.
If the dry cell voltage is 1.5V and during 1 hour of power generation it uses 1.2g of zinc, this 1.2g of zinc will be equivalent of 1.5 watt-hours.
Second part of your question was about cost effectivness.
If you imagine that 1 killowatt-hour is equivalent to 800 grams of zinc, a typical modern houshold (at the rate it consumes electricity) would consume something between 5 - 10 tons of zinc per year!!!
First of all, you wouldn't be able to supply that much zinc and, if you could, it would be terribly expensive ... so, you have got wires through which electricity is delivered to your home.
Regards,
IanP

dry battery

If you want to know all the gory details, see chapter 8 of the very nice "Handbook of Batteries":