8th Grade > Chemistry
COMBUSTION AND FLAME MCQs
Total Questions : 56
| Page 1 of 6 pages
Answer: Option B. -> Ignition temperature should be above room temperature.
:
B
Ignition temperature is the lowest temperature at which a substance catches fire. If the ignition temperature of afuel is lower than the room temperature, then it can catch fire very easily.
Therefore for an ideal fuel, the ignition temperature should be higher than the room temperature.
:
B
Ignition temperature is the lowest temperature at which a substance catches fire. If the ignition temperature of afuel is lower than the room temperature, then it can catch fire very easily.
Therefore for an ideal fuel, the ignition temperature should be higher than the room temperature.
Answer: Option B. -> Inflammable substance
:
B
The given picture is a warning signal indicating that the substance kept inside thebox is a inflammable substance. Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances. Examples of inflammable substances are petrol, diesel, LPG, etc.
:
B
The given picture is a warning signal indicating that the substance kept inside thebox is a inflammable substance. Substances which have very low ignition temperature and can easily catch fire with a flame are called inflammable substances. Examples of inflammable substances are petrol, diesel, LPG, etc.
Answer: Option B. -> carbon monoxide
:
B
Incomplete combustion takes place when sufficient amount of oxygen is not present. Incomplete combustion of fuels containing carbon like wood, coal, methane, petroleum, etc releases carbon monoxide (CO) gas which is a very poisonous gas.
:
B
Incomplete combustion takes place when sufficient amount of oxygen is not present. Incomplete combustion of fuels containing carbon like wood, coal, methane, petroleum, etc releases carbon monoxide (CO) gas which is a very poisonous gas.
Answer: Option B. -> electrical fires
:
B
Water is a good fire extinguisher. But, water cannot be used to extinguish electrical fires. This is because water is a good conductor of electricity. It can cause electric shock and can harm the person who is trying to put it off.
:
B
Water is a good fire extinguisher. But, water cannot be used to extinguish electrical fires. This is because water is a good conductor of electricity. It can cause electric shock and can harm the person who is trying to put it off.
Answer: Option B. -> Spontaneous combustion
:
B
The type of combustion in which a material suddenly bursts into flames, without any external heat supply is called spontaneous combustion. For example, substances like phosphorus and sodium burn when kept open at room temperature.
:
B
The type of combustion in which a material suddenly bursts into flames, without any external heat supply is called spontaneous combustion. For example, substances like phosphorus and sodium burn when kept open at room temperature.
Answer: Option B. -> Phosphorus
:
B
When a matchstick strikes on striking surface of a matchbox, the heat of the friction causes a reaction between the potassium chlorate in the match head and phosphorus in the striking surface.
:
B
When a matchstick strikes on striking surface of a matchbox, the heat of the friction causes a reaction between the potassium chlorate in the match head and phosphorus in the striking surface.
Answer: Option B. -> False
:
B
Whenever there is some unburnt residue in the product gases, the particles diffuse light passing through them and we see it as smoke.
If oxygen supply is limited, it will result in unburnt suspended particles in product gases which do not get oxygen to react with. And when there are non-inflammable impurities, they too will not burn and will result in ash or suspended particles.
:
B
Whenever there is some unburnt residue in the product gases, the particles diffuse light passing through them and we see it as smoke.
If oxygen supply is limited, it will result in unburnt suspended particles in product gases which do not get oxygen to react with. And when there are non-inflammable impurities, they too will not burn and will result in ash or suspended particles.
Answer: Option B. -> Asthma
:
B
Suspended particulate matter (SPM) refers tomicroscopic solid or liquid matter suspended in the Earth's atmosphere.Air pollutants consist of gaseous pollutants, odours, and SPM, (suspended particulate matter) such as dust, fumes, mist, and smoke. The high concentration of these in and nearurban areas causes severe pollution to the surroundings.High amount of SPM in airleads to respiratory problems andlung related diseases like asthma.
:
B
Suspended particulate matter (SPM) refers tomicroscopic solid or liquid matter suspended in the Earth's atmosphere.Air pollutants consist of gaseous pollutants, odours, and SPM, (suspended particulate matter) such as dust, fumes, mist, and smoke. The high concentration of these in and nearurban areas causes severe pollution to the surroundings.High amount of SPM in airleads to respiratory problems andlung related diseases like asthma.
Answer: Option B. -> False
:
B
The lowest temperature at which a substance catches fire is its ignition temperature. The ignition temperature of kerosene is about 600C. Hence, it does not catch fire by itself at room temperature.
:
B
The lowest temperature at which a substance catches fire is its ignition temperature. The ignition temperature of kerosene is about 600C. Hence, it does not catch fire by itself at room temperature.
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