The ignition temperature for natural gas is between 1100 and 1200 degrees.

The ignition temperature for natural gas is between 1100 and 1200 degrees.

• A. Over 9000 degrees
• B. Approximately 1500 degrees
• C. Between 1100 degrees and 1200 degrees
• D. Between 1700 degrees and 2000 degrees

Answer: (C)

The key idea is the autoignition (ignition) temperature of natural gas, which is the temperature at which the gas-air mix can ignite without an external flame. For natural gas, which is mainly methane, this temperature is about 1100°F (roughly 595°C). So a statement that the ignition temperature lies between 1100 and 1200 degrees is correct, assuming the degrees are Fahrenheit as typically used in safety contexts. Why the other ranges don’t fit: 9000 degrees is far beyond any practical ignition temperature, so it’s not plausible. 1500 degrees would be far higher than the usual autoignition range for natural gas (and if interpreted as Celsius, it’s unrealistic for this gas). 1700–2000 degrees is also far above the typical autoignition point. In short, natural gas ignites around 1100°F, so the middle choice matches the known value.

The key idea is the autoignition (ignition) temperature of natural gas, which is the temperature at which the gas-air mix can ignite without an external flame. For natural gas, which is mainly methane, this temperature is about 1100°F (roughly 595°C). So a statement that the ignition temperature lies between 1100 and 1200 degrees is correct, assuming the degrees are Fahrenheit as typically used in safety contexts.

Why the other ranges don’t fit: 9000 degrees is far beyond any practical ignition temperature, so it’s not plausible. 1500 degrees would be far higher than the usual autoignition range for natural gas (and if interpreted as Celsius, it’s unrealistic for this gas). 1700–2000 degrees is also far above the typical autoignition point. In short, natural gas ignites around 1100°F, so the middle choice matches the known value.