Question

Give reasons for the following:
1. A circular blackish ring is formed on a glass slide kept above the yellow zone of flame.
2. You are advised not to sleep in a closed room with burning or smoldering coal fire in it.
3. Wood shavings burn easier than a log of wood.
4. Cooking oil catches fire when a frying pan is kept on the stove for a long time.
5. We need to take special care in storing kerosene oil as compared to storing wood.​

Answer 1

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→ A circular blackish ring is formed on the glass plate/slide. It indicates the deposition of unburnt carbon particles present in the luminous zone of the flame.

→ Incomplete combustion of coal releases many poisonous gases like carbon monoxide in the environment. This carbon monoxide gas is fatal to health, can lead to coma and even death of the persons sleeping in that room.

→ The answer is two folds. It is the nature of combustion reaction. First as the others highlighted it is due to having higher surface area for wood to catch fire. That is why wood chips catch fire relatively easier and burn faster than a wooden log.

→ Cooking oil catches fire when frying pan is kept for long on a burning stove. Oil catches fire when your cooking oil becomes too hot. When heating, oils first start to boil, then they'll start smoking, and then they'll catch on fire. Most vegetable oils have a smoking point around 450°F.

→ Kerosene oil has low ignition temperature which means they can catch fire easily compared to coal. So, to store Kerosene more care to be taken than coal.

Thanks !

Answer 2

Answer:

Explanation:

1. A circular blackish ring on the glass plate kept over the candle flame indicates the luminous zone

2.We are advised never to sleep in a room with burning coal fire in it because the burning of coal emits carbon dioxide in the air which is harmful for us. Also, the incomplete combustion of coal can emit carbon monoxide which is a very harmful gas and can cause suffocation and even death to the person.

3. It is the nature of combustion reaction. First as the others highlighted it is due to having higher surface area for wood to catch fir