Which of the following reactions represents the combustion of methane?

Question

Examoogle · Accepted Answer

The correct answer is Option A: CH ₄ + O ₂ → CO ₂ + 2H ₂ O. Combustion is a chemical process in which a substance reacts rapidly with oxygen gas ($O_2$) to release energy in the form of heat and light. Complete combustion of a hydrocarbon like methane ($CH_4$) produces carbon dioxide ($CO_2$) and water ($H_2O$) as products.

Step-by-Step Solution & Concepts:
Combustion is a chemical process in which a substance reacts rapidly with oxygen gas ($O_2$) to release energy in the form of heat and light. Complete combustion of a hydrocarbon like methane ($CH_4$) produces carbon dioxide ($CO_2$) and water ($H_2O$) as products.

Working Principle: Methane ($CH_4$) undergoes a exothermic redox reaction with oxygen ($O_2$) when ignited. Carbon in methane is oxidized to carbon dioxide ($CO_2$), while hydrogen is oxidized to water vapor ($H_2O$). The balanced chemical reaction requires 1 molecule of $CH_4$ to react with 2 molecules of $O_2$ to form 1 molecule of $CO_2$ and 2 molecules of $H_2O$.

Key Formulas: $	ext{CH}_4 + 2	ext{O}_2 ightarrow 	ext{CO}_2 + 2	ext{H}_2	ext{O} + \Delta H$

Key Points: Complete combustion of any hydrocarbon yields carbon dioxide ($CO_2$) and water ($H_2O$).; Incomplete combustion (limited oxygen supply) yields carbon monoxide ($CO$) or soot ($C$).; Methane ($CH_4$) is the primary constituent of natural gas (~90%) and Compressed Natural Gas (CNG).; Combustion is an exothermic reaction because energy is released when chemical bonds are formed in $CO_2$ and $H_2O$.

Advantages: High energy density per unit mass among fossil fuels.; Produces fewer pollutants (like particulates or sulfur dioxide) compared to coal and oil.

Disadvantages: Releases carbon dioxide ($CO_2$), a primary greenhouse gas contributing to global warming.; Incomplete combustion releases toxic carbon monoxide ($CO$) gas.

Applications: Domestic gas stoves and water heaters using Natural Gas/PNG.; Fuel source in Compressed Natural Gas (CNG) vehicles.; Gas turbine power plants for electricity generation.

Additional Info: Option B (CH₄ + H₂O → CO + H₂) represents steam methane reforming, a industrial method to produce hydrogen gas.. Option C (CH₄ + Cl₂ → CH₃Cl + HCl) represents free radical chlorination (substitution reaction) of methane in presence of light.. Option D represents incomplete combustion, but the chemical equation as written is unbalanced.

Answer: A is correct — Option A represents the correctly balanced chemical equation for the complete combustion of methane, forming carbon dioxide and water.

Exam Tip: Questions on hydrocarbon reactions frequently test the difference between complete combustion ($CO_2 + H_2O$) and substitution reactions ($Cl_2/h
u$). Look for oxygen as a reactant to quickly identify combustion.

Examoogle · Answer

Option B: CH ₄ + H ₂ O → CO + H ₂

Examoogle · Answer

Option C: CH ₄ + Cl ₂ → CH ₃ Cl + HCl

Examoogle · Answer

Option D: CH ₄ + O ₂ → CO + H ₂ O

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Discussion (0)

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Related Questions

Discussion (0)