Mnemonics: Purification and Characterisation of Organic Compounds | Chemistry Class 12 - NEET PDF Download

 Purification Methods

• Crystallization

  • Mnemonic: "Cool Crystals Climb Slowly."

  • Explanation: Crystallization occurs when a solution cools and forms crystals, slowly allowing pure crystals to climb or form.

• Sublimation

  • Mnemonic: "Sublime Solids Skip Liquids."

  • Explanation: Sublimation is when solids skip the liquid phase and directly turn into gas, a "sublime" and efficient separation process.

• Distillation

  • Mnemonic: "Distillation Divides By Boiling."

  • Explanation: Distillation separates liquids by their boiling points, making it effective in purifying volatile substances.

• Differential Extraction

  • Mnemonic: "Different Solvents Divide."

  • Explanation: In differential extraction, different solvents help separate components of a mixture based on their solubility.

• Chromatography

  • Mnemonic: "Chromatography Cuts Components."

  • Explanation: Chromatography separates a mixture into individual components, often resulting in distinct bands or "cuts."
    

Qualitative Analysis

• Detection of Extra Elements

  • Mnemonic: "Nasty Sulfur Puts Halogens on Trial."

  • Explanation: Lassaigne’s test is used to detect Nitrogen, Sulfur, Phosphorus, and Halogens. The phrase helps remember the four elements tested in the analysis: Nitrogen, Sulfur, Phosphorus, and Halogens.

• Detection of Functional Groups

  • Hydroxyl Group (Alcoholic & Phenolic)

    • Mnemonic: "Hydroxyl Hides in Alcohols and Phenols."

    • Explanation: The Hydroxyl group (-OH) is found in both Alcoholic and Phenolic compounds. This mnemonic emphasizes that the hydroxyl group "hides" in both types of compounds.

  • Carbonyl Group (Aldehyde & Ketones)

    • Mnemonic: "Carbonyl Catches Aldehydes and Ketones."

    • Explanation: The Carbonyl group (-C=O) is present in both Aldehydes and Ketones. The mnemonic helps you remember that this group “catches” or identifies both.

  • Carboxyl Group

    • Mnemonic: "Carboxyl Creates Organic Acids."

    • Explanation: The Carboxyl group (-COOH) is characteristic of organic acids like acetic acid. This mnemonic links carboxyl with its role in forming acids.

  • Amino Group

    • Mnemonic: "Amino Adds Nitrogen."

    • Explanation: The Amino group (-NH2) contains Nitrogen and is found in amines. This mnemonic helps emphasize the key element Nitrogen in the amino group.

Identification and Characterisation of Organic Compounds

• Physical Properties

  • Mnemonic: "Melting Boiling Points Reveal Purity."

  • Explanation: Melting point and boiling point are key physical properties used to identify and characterize organic compounds by assessing their purity.

• Spectroscopic Techniques

  • UV-Visible Spectroscopy

    • Mnemonic: "UV-Visible Detects Absorption."

    • Explanation: UV-Visible spectroscopy detects the absorption of ultraviolet and visible light by compounds, helping identify their structure.

  • Infrared (IR) Spectroscopy

    • Mnemonic: "Infrared Identifies Bonds."

    • Explanation: IR spectroscopy identifies vibrations in chemical bonds, helping determine functional groups and molecular structure.

  • Nuclear Magnetic Resonance (NMR) Spectroscopy

    • Mnemonic: "NMR Notes Nuclear Spins."

    • Explanation: NMR spectroscopy detects the nuclear spins of atoms, revealing detailed information about the structure of organic compounds.

  • Mass Spectrometry

    • Mnemonic: "Mass Spectrometry Measures Fragments."

    • Explanation: Mass spectrometry breaks down a compound into smaller ions and measures their mass, revealing the structure of the compound.