Carbon and Sulfuric Acid Reaction | C + H₂SO₄

Concentrated sulfuric acid is an oxidizing acid which can oxidize carbon to carbon dioxide while sulfuric acid is reduced to sulfur dioxide. This is a redox reaction because oxidation numbers of carbon and sulfur atoms are changed. We will discuss about characteristics of carbon and sulfuric acid reaction in this tutorial.

C + H₂SO₄ → CO₂ + SO₂ + H₂O

Reaction conditions

Hot, concentrated sulfuric acid should be used to oxidize carbon to carbon dioxide. During that time, sulfur atom in sulfuric acid is reduced to sulfur dioxide. Therefore, this is a redox reation.

Products of the reaction

• Carbon is oxidized to colorless carbon dioxide (CO₂) gas. Oxidation number of carbon is increased from 0 to +4.
• Sulfuric acid is reduced to colorless sulfur dioxide gas. Oxidation number of sulfur is reduced from +6 to +4. Therefore, hot concentrated sulfuric acid behave as an oxidizing acid.
• Water is formed also as a product.

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How to balance the reaction of carbon an sulfuric acid

Because, this reaction is a redox reaction, we can follow theories of balancing redox chemical equations. Below, each step of balancing is explained in detail.

Identify which elements are oxidized and reduced

We have already learned, carbon is oxidized and and sulfur atom in sulfuric acid is reduced.

Number of oxidized and reduced atoms should be same

• Number of carbon atoms in the left side (1) and right side (1) of the reaction is same and do not need to balance them.
• Number of sulfur atoms in the left side (1) and right side (1) of the reaction is same and do not need to balance them.

What is the difference of oxidation numbers of respective atoms?

• Oxidation number of carbon is increased from 0 to +4. Therefore, oxidation number difference for carbon is 4.
• Oxidation number of sulfur is reduced from +4 to +4. Therefore, oxidation number difference for carbon is 2.

Exchange oxidation number difference in simplest ratio

Oxidation number difference for carbon and sulfur is 4 and 2 respectively. Therefore ratio is 4:2. You can simplify this ratio as 2:1. Nw, exchange differences.

C + 2H₂SO₄ → CO₂ + 2SO₂ + H₂O

Now, oxidizing and reducing atoms are balanced. Lets balance rest of atoms by observing left and right side of reaction.

C + 2H₂SO₄ → CO₂ + 2SO₂ + 2H₂O

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Questions asked by students

Ask your question and find the answer free.

h2so4 or "sulfuric acid" or "sulphuric acid"

From both names and chemical formula, define a same compound. Sulfuric acid is used in americaal english and sulphuric acid is used in british english.

Which gases are produced when sulphuric acid reacts with carbon

Two gases are produced when sulphuric acid reacts with carbon. They are sulphur dioxide and carbon dioxide. Both are acidic gases and sulfur dioxide is slightly acidic than carbon dioxide.

What will happen if dilute sulphuric acid is added to carbon?

Dilute sulphuric acid does not show characteristics of oxidizing acid. Therefore, dilute sulphuric acid does not react with carbon. Only hot concentrated sulphuric acid show characteristics of being a oxidizing acid.

Describe physical States of every reactants and products

Carbon is at solid state and sulfuric acid exists as a aqueous solution. From the products, Sulphur dioxide and carbon dioxide are in the gaseous state. Water is at liquid state.

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