Question

Rancho (from Three Idiots) is a curious guy and he is very good in chemistry. Once he removed a battery from a clock and started opening it up battery from a clock and started opening it up. Which of the following observation of Rancho were TRUE?

• A. There is a cylindrical zinc container.
• B. A graphite rod is there in the centre and it is surrounded by powdered manganese powder.
• C. The space between the cylindrical container and graphite rod is filled with a moist paste of ammonium chloride and zinc chloride.
• D. None of these.

Answer 1

Answer: (A), (B), (C)

The correct options are
A There is a cylindrical zinc container.
B A graphite rod is there in the centre and it is surrounded by powdered manganese powder.
C The space between the cylindrical container and graphite rod is filled with a moist paste of ammonium chloride and zinc chloride.

First we have to find out which type of battery Rancho was using.
As it is used in the clock, it will be Zinc – carbon dry cell as we discussed in the videos.
What do we know about zinc-carbon dry cell?
A dry cell is a compact form of the Leclanche cell. It consists of a cylindrical zinc container which acts as the anode. A graphite rod placed in the centre (but not touching the base) acts as the cathode. The space between the anode and the cathode is so packed that the zinc container is in touch with a metal cap and the cylinder is sealed at the top with pitch. The zinc container is covered with cardboard to protect it from the atmosphere.
So, now we know if we try to open a clock battery. It will look like this.

To know more about it, you have to stay curious like Rancho and wait for the next question.