Question

Choose the correct statement about inflammable substances from the following. They have

• A. low ignition temperature and cannot catch fire easily
• B. high ignition temperature and can catch fire easily
• C. low ignition temperature and can catch fire easily.
• D. high ignition temperature and cannot catch fire easily.

Answer 1

The correct option is C

low ignition temperature and can catch fire easily.

The explanation for the correct option:

Option (C): Low ignition temperature and can catch fire easily

1. Combustible substances are those that burn in the presence of air to produce heat and light. Example: petrol, coal
2. Inflammable substances are highly combustible i.e. they catch fire easily as they have low ignition temperatures.
3. The lowest temperature at which a substance catches fire and undergoes combustion, releasing heat and light, is referred to as the ignition temperature.
4. Therefore, for a substance to be inflammable both the conditions should be fulfilled.
5. Hence, it is the correct option.

The explanation for the incorrect option:

Option (A): low ignition temperature and cannot catch fire easily

1. Inflammable substances are substances that are highly combustible in nature i.e. catches fire easily. Example: petrol
2. They possess low ignition temperatures.
3. Hence, it is the incorrect option.

Option (B): high ignition temperature and can catch fire easily

1. Inflammable substances are substances that have a high rate of combustion. Example: Alcohol, petrol
2. These substances should have a low ignition temperature to ensure that the combustion rate is fast.
3. Substances with high ignition temperature are not classified as inflammable substances because combustion takes place at a higher temperature and the combustion rate is slow.
4. Hence, It is an incorrect option.

Option (D): high ignition temperature and cannot catch fire easily.

1. Inflammable substances must meet two conditions i.e. they must be highly combustible and have a low ignition temperature.
2. The ignition temperature is the lowest temperature at which a substance ignites and burns, emitting heat and light. As a result, it's difficult to burn compounds with high ignition temperatures.
3. Hence, it is an incorrect option.

Therefore, inflammable substances should have a low ignition temperature and can catch fire easily.