Alcohols and Their Reactions
48 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of reaction is the conversion of an alcohol to an alkene?

  • Dehydration (correct)
  • Halogenation
  • Reduction
  • Oxidation

    • Tertiary alcohols are easily oxidized using acidified potassium dichromate(VI).

    False

    What color change is observed when an alcohol is oxidized with potassium dichromate(VI)?

    orange to green

    Primary alcohols can be oxidized to aldehydes, and further oxidized to ______.

    <p>carboxylic acids</p> Signup and view all the answers

    Match the following alcohols with their oxidation products:

    <p>Primary Alcohol = Aldehyde (then Carboxylic Acid) Secondary Alcohol = Ketone Tertiary Alcohol = No Reaction</p> Signup and view all the answers

    Which reagent can be used to convert an alcohol to an iodoalkane?

    <p>Red phosphorus and iodine</p> Signup and view all the answers

    Haloalkanes contain nonpolar bonds due to the similar electronegativity of carbon and halogen atoms.

    <p>False</p> Signup and view all the answers

    What type of product is formed when a secondary alcohol is oxidized?

    <p>ketone</p> Signup and view all the answers

    What is the primary function of the condenser in a reflux apparatus?

    <p>To cool and condense vapours, returning them to the flask</p> Signup and view all the answers

    In a distillation setup, the liquid with the higher boiling point evaporates first.

    <p>False</p> Signup and view all the answers

    What property difference allows a separating funnel to separate liquids?

    <p>density</p> Signup and view all the answers

    The purer a substance, the ______ to the databook boiling point it will be.

    <p>closer</p> Signup and view all the answers

    Match each piece of apparatus with its primary use:

    <p>Reflux Apparatus = Heating a reaction mixture while preventing loss of volatile substances Distillation Apparatus = Separating liquids with different boiling points Separating Funnel = Separating liquids with different densities Thiele Tube = Measuring boiling point</p> Signup and view all the answers

    What is the purpose of using an inverted capillary tube when determining a substances boiling point?

    <p>To allow the condensed liquid to be drawn into</p> Signup and view all the answers

    Redistillation is done to obtain a less pure product.

    <p>False</p> Signup and view all the answers

    When determining boiling point, what observation is made to determine the exact boiling point temperature?

    <p>condensation</p> Signup and view all the answers

    The fingerprint region of an IR spectrum is unique to each molecule and can be used to identify it.

    <p>True</p> Signup and view all the answers

    The absorption of infrared radiation by atmospheric gases containing C=O, O–H, and C–H bonds, such as CO₂, H₂O, and CH₄, is linked to ______.

    <p>global warming</p> Signup and view all the answers

    Which of the following is NOT a use of Infrared Spectroscopy?

    <p>Identifying different molecules</p> Signup and view all the answers

    Match the following steps in TOF mass spectrometry with their corresponding descriptions.

    <p>Ionization = Positively charged ions are accelerated towards a negatively charged detection plate. Acceleration = A sample is vaporized and injected into the mass spectrometer where a high voltage is passed over the chamber. Ion Drift = The ions are deflected by a magnetic field into a curved path. Detection = When positive ions hit the negatively charged detection plate, they gain an electron, producing a flow of charge. Analysis = The current values are used in combination with the flight times to produce a spectra print-out with the relative abundance of each isotope displayed.</p> Signup and view all the answers

    What is a nucleophile described as?

    <p>An electron pair donor</p> Signup and view all the answers

    Nucleophilic substitution can occur for tertiary haloalkanes.

    <p>False</p> Signup and view all the answers

    What is the purpose of the magnetic field in TOF mass spectrometry?

    <p>The magnetic field deflects the ions into a curved path, allowing for separation based on their charge and mass.</p> Signup and view all the answers

    What does the 'm/z' value in mass spectrometry represent?

    <p>Mass to charge ratio</p> Signup and view all the answers

    What type of product is formed when haloalkanes react with aqueous potassium hydroxide?

    <p>alcohols</p> Signup and view all the answers

    The greater the Mr of the halogen in the polar bond, the ______ the bond enthalpy.

    <p>lower</p> Signup and view all the answers

    The molecular ion peak in a mass spectrum is the peak furthest to the left, representing the ion with the lowest mass-to-charge ratio.

    <p>False</p> Signup and view all the answers

    Match the nucleophiles with their products after reaction with haloalkanes:

    <p>:NH3 = Amines :OH- = Alcohols CN- = Nitriles</p> Signup and view all the answers

    Explain how the relative abundance of each isotope is determined in TOF mass spectrometry.

    <p>The relative abundance of each isotope is determined by measuring the current produced when the ions hit the detection plate. A greater current indicates a higher abundance of that specific isotope.</p> Signup and view all the answers

    What role do chlorine radicals play in the breakdown of ozone?

    <p>They act as catalysts and are regenerated.</p> Signup and view all the answers

    CFCs are haloalkanes containing carbon, chlorine, and fluorine atoms, but not oxygen.

    <p>True</p> Signup and view all the answers

    What is the overall equation for the breakdown of ozone by chlorine radicals?

    <p>2O₃ → 3O₂</p> Signup and view all the answers

    Which of the following is a common anhydrous salt used for drying compounds?

    <p>Magnesium sulphate</p> Signup and view all the answers

    Addition reactions are less sustainable than substitution reactions.

    <p>False</p> Signup and view all the answers

    What is the process called that involves converting an organic compound into a product through multiple stages?

    <p>Multi-stage synthesis</p> Signup and view all the answers

    Bromine water is used to test for __________.

    <p>unsaturation</p> Signup and view all the answers

    Match the following tests with the substances they detect:

    <p>Bromine water = Unsaturation Acidified potassium dichromate = 1°/2° alcohols Tollens’ reagent = Aldehydes Aqueous silver nitrate with ethanol = Haloalkanes</p> Signup and view all the answers

    When analyzing synthetic routes, why is it preferable to choose reagents with fewer safety concerns?

    <p>They minimize health risks.</p> Signup and view all the answers

    The identification of functional groups can be performed using various tests.

    <p>True</p> Signup and view all the answers

    What effect does infrared (IR) radiation have on covalent bonds?

    <p>It causes them to vibrate and absorb energy.</p> Signup and view all the answers

    Which functional group is identified by a sharp peak in the range of 1620-1680 cm-1?

    <p>C=C Unsaturated Group</p> Signup and view all the answers

    A broad, smooth peak in the IR spectrum indicates the presence of a carboxylic acid functional group.

    <p>False</p> Signup and view all the answers

    What does the IR spectrum primarily measure when analyzing organic compounds?

    <p>Absorbance of infrared radiation by functional groups</p> Signup and view all the answers

    The characteristic peak range for the C=O carbonyl group is ________ cm-1.

    <p>1680-1750</p> Signup and view all the answers

    Match the functional groups with their characteristic peak ranges:

    <p>-OH Alcohol Group = 2300-3550 cm-1 C=C Unsaturated Group = 1620-1680 cm-1 C=O Carbonyl Group = 1680-1750 cm-1 -OH Acid Group = 2500-3300 cm-1</p> Signup and view all the answers

    Which functional group can be identified by both a C=O bond peak and a broad O–H bond peak?

    <p>Carboxylic Acid</p> Signup and view all the answers

    At approximately what cm⁻¹ will most organic compounds produce a peak due to C–H bonds?

    <p>3000</p> Signup and view all the answers

    Infrared spectroscopy can distinguish between aldehydes and ketones solely by their C=O absorption peaks.

    <p>False</p> Signup and view all the answers

    Study Notes

    Alcohols

    • Alcohols contain an -OH group and follow the general formula CnH2n+1OH.
    • They can be classified as primary (1°), secondary (2°), or tertiary (3°) depending on the position of the hydroxyl group.
    • Alcohols are polar molecules due to the large electronegativity difference between carbon and oxygen, allowing hydrogen bonding with water.
    • This hydrogen bonding makes alcohols water-soluble.
    • Alcohols have both hydrogen bonding and van der Waals forces, making them less volatile than alkanes.
    • Alcohols combust in air, reacting with oxygen to form carbon dioxide and water, releasing energy.
    • (Example: 2CH3OH + 3O2 → 2CO2 + 4H2O)

    Reactions of Alcohols

    • Combustion: Alcohols react with oxygen to form carbon dioxide and water, releasing energy, making them good fuels.
    • Reaction with halogenating agents: Alcohols can react with halogenating agents (like PCl3) to form haloalkanes, replacing the -OH group with a halogen. This reaction can be used as a test for alcohols.
    • Elimination Reactions: Alkenes can be produced from alcohols through dehydration, where a molecule of water is removed, typically by heating the alcohol with concentrated phosphoric acid.
    • Oxidation of Alcohols:
      • Primary alcohols can be oxidised to aldehydes and further to carboxylic acids with acidified potassium dichromate(VI).
      • Secondary alcohols are oxidised to ketones with acidified potassium dichromate(VI).
      • Tertiary alcohols are not easily oxidised.

    Haloalkanes

    • Haloalkanes contain polar bonds because halogens are more electronegative than carbon.
    • This creates a partial positive charge on the carbon and a partial negative charge on the halogen.
    • They are classified as primary, secondary, or tertiary based on the position of the halogen in the carbon chain.
    • Reactivity varies between halogens, decreasing down the group from fluorine to iodine. This is due to decreasing bond enthalpy.

    Substitution Reactions of Haloalkanes

    • Haloalkanes react with aqueous alkali (like NaOH) in a nucleophilic substitution reaction to form alcohols.
    • Haloalkanes react with ethanolic potassium hydroxide (KOH) to form alkenes via an elimination reaction.
    • Haloalkanes react with aqueous silver nitrate to form precipitates, with the colour of the precipitate indicating the halide ion. The rate of precipitate formation correlates to the stability of the haloalkane. Iodoalkanes are hydrolysed faster than bromoalkanes, which are faster than chloroalkanes.

    Nucleophilic Substitution Mechanism

    • Nucleophiles, electron-pair donors, attack haloalkanes in a specific mechanism.
    • This depends on the type of nucleophile and the structure of the haloalkane (primarily 1° and 2°).

    Environmental Concerns

    • Organohalogen compounds, like CFCs, can break down the ozone layer in the atmosphere through a catalytic reaction.
    • Ultraviolet radiation initiates the breakdown.

    Organic Synthesis

    • Practical Skills: Heating under reflux (for reactions that need extended heating) and distillation (to separate liquids with different boiling points) are important techniques.
    • Synthetic Routes: In the preparation of an organic compound, choosing appropriate synthetic routes based on reagents, byproducts, and reaction conditions to ensure efficiency and safety is important.
    • Multi-stage Synthesis: In the preparation of complex organic molecules, steps involving intermediate molecules can improve efficiency.

    Analytical Techniques

    • Infrared Spectroscopy (IR): IR radiation causes covalent bonds to vibrate, and the absorbed energy is used to identify functional groups by their unique absorption patterns in the IR spectrum.

    • Mass Spectrometry: This is used to identify molecules and determines the mass of the organic molecule. It shows the breakdown of the original molecule and identifies the fragments.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    OCR A Chemistry A-level Alcohols, Haloalkanes & Analysis Detailed Notes PDF

    Description

    This quiz covers the chemical properties of alcohols, including their structure, classifications, and reactions such as combustion and reaction with halogenating agents. It is designed to test your understanding of alcohol chemistry and their significance in organic reactions.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser