4 Most FAQ’s of Carbon and its Compounds Chapter in Class 10th Physical Science (TS/AP)

8 Marks

LAQ-1 : Explain the cleaning action of soap.

Introduction

Soap is an essential daily use item known for its effective cleaning properties. Understanding the science behind its cleaning action involves examining the structure of soap molecules and their interaction with water and dirt. This explanation will shed light on how soap performs its primary function of cleaning.

Composition of a Soap Molecule

1. Hydrophilic End (Ionic or Polar Part):
   • Attraction: Attracts to water.
   • Role: Dissolves the soap in water.
2. Hydrophobic End (Non-Polar Part):
   • Attraction: Attracts to oils or grease but repels water.
   • Role: Binds with dirt or oil, facilitating its removal.

Mechanism of Cleaning

1. Placing in Water:
   • Soap Behavior: Molecules arrange with hydrophilic ends outwards (interacting with water) and hydrophobic ends inwards.
2. Attraction to Dirt:
   • Action: Hydrophobic ends attach to dirt on surfaces.
3. Micelle Formation:
   • Structure: Soap molecules form micelles, trapping dirt in the center.
   • Interaction: Hydrophilic ends on the outer part interact with water.
4. Removal of Dirt:
   • Process: Micelles are suspended in water, carrying away dirt during rinsing.

Summary

In summary, the effectiveness of soap in cleaning is derived from its unique molecular structure, with hydrophilic and hydrophobic ends. The hydrophilic end’s affinity for water and the hydrophobic end’s ability to bind with dirt or oil enable the formation of micelles. These micelles encapsulate dirt and oil particles, which are then easily rinsed away with water, leaving the surface clean. This fundamental understanding of soap’s mechanism is crucial in appreciating its role in daily hygiene and cleaning processes.

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LAQ-2 : Observe the above table and answer the following questions.

Organic compound	Methane	Ethane	Propane	Butene	Pentyne	Hexyne
Formula	CH4	C2H4	C3H6	C4H8	C5H8	C6H10

1.Write the general formula of Alkanes.

2.Mention the names of unsaturated hydrocarbons.

3.Write the homologous series of alkynes.

4.Write the formula of hexyne.

Introduction

This section aims to address questions related to hydrocarbons, focusing on alkanes, unsaturated hydrocarbons, alkynes, and hexyne. The information provided will clarify these chemical concepts.

1. General Formula of Alkanes
   • Formula: C_n​H_2n+2​
   • Explanation: Alkanes are saturated hydrocarbons. The formula C_n​H_2n+2​ indicates that for every n carbon atoms, there are 2n+2 hydrogen atoms.
2. Names of Unsaturated Hydrocarbons
   • Listed Hydrocarbons: Propane (C₃​H₆​), Butene (C₄​H₈​), Pentyne (C₅​H₈​), Hexyne (C₆​H₁₀​).
   • Explanation: These are unsaturated hydrocarbons with either double or triple bonds between carbon atoms, including alkenes and alkynes.
3. Homologous Series of Alkynes
   • Series: Ethyne (C₂​H₂​), Propyne (C₃​H₄​), Butyne (C₄​H_6​), Pentyne (C₅​H₈​), Hexyne (C₆​H_10​).
   • Explanation: This series represents alkynes, where each compound differs by a −CH₂​ unit.
4. Formula of Hexyne
   • Formula: C₆​H₁₀​
   • Explanation: Hexyne is an alkyne with six carbon atoms and a triple bond, hence its formula is C₆​H₁₀​.

Summary

In summary, the general formula for alkanes is C_n​H_2n+2​, unsaturated hydrocarbons include compounds like Propane and Butene, alkynes follow a homologous series, and Hexyne is represented by the formula C₆​H₁₀​. Understanding these concepts is essential in the study of hydrocarbons.

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LAQ-3 : Write the types of Allotropes of carbon. Give any three examples of each.

Introduction

Allotropy refers to the existence of an element in multiple forms with different physical properties but similar chemical properties. Carbon is a notable example, existing in both amorphous and crystalline allotropes.

Types of Carbon Allotropes:

1. Amorphous Allotropes:
2. Crystalline Allotropes:

Amorphous Allotropes:

1. Coal:
   • Source: Natural
   • Use: Major fuel source
2. Coke:
   • Source: Derived from coal
   • Use: Fuel and reducing agent in smelting iron ore
3. Wood Charcoal:
   • Source: Partial burning of wood
   • Use: Fuel, art, filtration

Features of Amorphous Allotropes: Amorphous allotropes like coal, coke, and wood charcoal have non-crystalline structures, leading to varying physical properties such as hardness and conductivity. These allotropes are commonly used as fuel or in industrial applications.

Crystalline Allotropes:

1. Diamond:
   • Structure: Tetrahedral bonding of each carbon atom to four others
   • Use: Gemstones, cutting tools
2. Graphite:
   • Structure: Flat planes of carbon atoms bonded to three others
   • Use: Lubricants, pencils
3. Buckminsterfullerene (C60):
   • Structure: Spherical molecules of 60 carbon atoms
   • Use: Research, nanotechnology

Features of Crystalline Allotropes: Crystalline allotropes, including diamond, graphite, and buckminsterfullerene, possess well-defined, ordered structures. These confer unique properties, such as diamond’s hardness, graphite’s slipperiness, and buckminsterfullerene’s spherical shape, making them useful in various applications.

Summary

Understanding carbon’s allotropes is key to comprehending its versatile nature and applications. The amorphous forms like coal and coke serve primarily as fuels, while crystalline forms like diamond and graphite are used in diverse fields from jewelry to lubrication. This distinction and their respective uses provide a foundational understanding of carbon chemistry.

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LAQ-4 : Write any 4 characteristics features of homologous series of organic compounds.

Introduction

In organic chemistry, homologous series represent groups of compounds with similar structures and properties. Understanding their characteristic features is vital for comprehending the behavior and utility of organic compounds.

Characteristic Features of Homologous Series:

1. Common General Formula:
   • Each series follows a general formula.
   • Examples include:
     • Alkanes:
       $$C_n H_{2n+2}$$
     • Alkenes:
       $$C_n H_{2n}​$$
     • Alkynes:
       $$C_n H_{2n-2}$$
     • Alcohols:
       $$C_n H_{2n+1}OH$$
2. Difference by CH2 Unit:
   • Adjacent compounds differ by a methylene (CH₂​) group.
   • This results in a molecular mass difference of 14 amu14amu.
   • Example: Difference between Methane (CH₄​) and Ethane (C₂​H₆​).
3. Similar Chemical Properties:
   • Compounds share similar chemical properties due to the same functional group.
   • Examples:
     • Alcohols with the −OH group
     • Aldehydes with the −CHO group
     • Carboxylic acids with the −COOH group
4. Gradation in Physical Properties:
   • A gradual change in physical properties like boiling point, melting point, and density is observed with an increase in molecular weight.
   • Example: Rising boiling points from Methane to Ethane to Propane in the Alkane series.

Summary

Homologous series in organic chemistry provide a systematic framework for classifying and understanding organic compounds. They showcase consistency in their structure and a predictable pattern in their physical and chemical properties. Recognizing these features is crucial for studying organic compounds, predicting their behavior, and applying this knowledge in various scientific and industrial applications.