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Carbon and its Compounds - Chemical properties of carbon compounds (combustion, oxidation, addition and substitution)

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Combustion: Carbon and its compounds burn in the presence of oxygen (O2O_2) to produce carbon dioxide (CO2CO_2), water (H2OH_2O), heat, and light. Saturated hydrocarbons generally give a clean blue flame, while unsaturated hydrocarbons give a yellow sooty flame due to incomplete combustion.

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Oxidation: Carbon compounds can be oxidized. Alcohols are converted into carboxylic acids using oxidizing agents like alkaline KMnO4KMnO_4 (Potassium Permanganate) or acidified K2Cr2O7K_2Cr_2O_7 (Potassium Dichromate) upon heating.

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Addition Reaction: Unsaturated hydrocarbons (alkenes and alkynes) add hydrogen (H2H_2) in the presence of catalysts like Nickel (NiNi) or Palladium (PdPd) to become saturated hydrocarbons. This process is known as hydrogenation.

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Substitution Reaction: Saturated hydrocarbons (alkanes) are generally unreactive. However, in the presence of sunlight, chlorine (Cl2Cl_2) replaces hydrogen atoms one by one. This is called a substitution reaction because one atom replaces another.

📐Formulae

CH4+2O2→CO2+2H2O+Heat and LightCH_4 + 2O_2 \rightarrow CO_2 + 2H_2O + \text{Heat and Light}

CH3CH2OH→Alkaline KMnO4+HeatCH3COOHCH_3CH_2OH \xrightarrow{\text{Alkaline } KMnO_4 + \text{Heat}} CH_3COOH

CH2=CH2+H2→NiCH3−CH3CH_2=CH_2 + H_2 \xrightarrow{Ni} CH_3-CH_3

CH4+Cl2→SunlightCH3Cl+HClCH_4 + Cl_2 \xrightarrow{Sunlight} CH_3Cl + HCl

💡Examples

Problem 1:

Identify the type of reaction: CH2=CH2+H2→NiCH3−CH3CH_2=CH_2 + H_2 \xrightarrow{Ni} CH_3-CH_3. Why is this reaction important in the food industry?

Solution:

This is an Addition Reaction (Hydrogenation).

Explanation:

In the food industry, this reaction is used to convert liquid vegetable oils (which contain long unsaturated carbon chains) into solid vegetable ghee (saturated fats) using a Nickel catalyst.

Problem 2:

What happens when ethanol (CH3CH2OHCH_3CH_2OH) is heated with alkaline KMnO4KMnO_4?

Solution:

CH3CH2OH+2[O]→CH3COOH+H2OCH_3CH_2OH + 2[O] \rightarrow CH_3COOH + H_2O

Explanation:

Ethanol undergoes oxidation to form ethanoic acid. Here, alkaline KMnO4KMnO_4 acts as an oxidizing agent, providing oxygen for the reaction.

Problem 3:

Explain why the burning of coal or petroleum sometimes produces a yellow flame and black smoke.

Solution:

This is due to Incomplete Combustion of carbon compounds.

Explanation:

If the supply of air (oxygen) is limited or if the fuel is highly unsaturated, the carbon atoms do not oxidize completely. This results in unburnt carbon particles which glow yellow and form soot (black smoke).

Chemical properties of carbon compounds (combustion, oxidation, addition and substitution)…