MT-MLS104L Inorganic and Organic Chemistry Lab

Laboratory Exam Overview

• Preliminary lab exam includes five main experiments focusing on various aspects of inorganic and organic chemistry.
• Main topics include solubility of organic compounds, reactions of hydrocarbons and alkyl halides, nomenclature of organic compounds, and lab safety.
• Review materials include a post-lab file, textbooks, and additional PDF resources.

Solubility of Organic Compounds

• Definition: Solubility refers to how much solute can dissolve in a specific amount of solvent.
• General Principle: “Like dissolves like” — polar solutes dissolve in polar solvents; nonpolar solutes dissolve in nonpolar solvents.
• Hydrogen Bonding: Compounds that can hydrogen bond with water typically exhibit higher solubility.
• Molecular Weight Impact: Increased molecular weight generally enhances intermolecular forces, reducing solubility.
• Branching: Branced chain compounds are more soluble than straight chain counterparts due to reduced molecular volume.
• Utility: Solubility informs identification of organic compounds and is crucial in separation techniques like extraction and chromatography.
• Common Solvents: Distilled water, 5% NaOH, 5% NaHCO3, 5% HCl, cold conc. H2SO4, diethyl ether are commonly used in solubility tests.

Classification of Compounds Based on Solubility

• S1 includes arylsulfonic acids, monofunctional carboxylic acids, amines, alcohols, and other small polar molecules.
• S2 comprises salts of organic acids, amino acids, and functional compounds with hydrophilic groups.
• A1 and A2 involve strong and weak organic acids respectively, with benzoic acid being a stronger acid than phenol.
• B Class: Aliphatic amines with eight or more carbons, anilines, and select ethers fall under this category.
• Miscellaneous (M): Neutral compounds with nitrogen or sulfur containing over five carbon atoms.
• N Class: Monofunctional alcohols, aldehydes, and ketones with 5 to 9 carbons are included, along with some aromatic compounds.
• I Class: Saturated hydrocarbons, haloalkanes, and deactivated aromatic compounds.

Reactions of Hydrocarbons and Alkyl Halides

• Samples: Include saturated (e.g., hexane) and unsaturated hydrocarbons (e.g., cyclohexene).
• Bromine Test: Useful to identify unsaturation; the disappearance of bromine color indicates a positive result.
• Baeyer’s Test: Tests for unsaturated hydrocarbons using alkaline KMnO4, confirmed by color change from purple to brown precipitate.
• Ethanolic Silver Nitrate Test: Targets secondary and tertiary alkyl halides; positive results yield colored precipitates based on halide type (chloride, bromide, iodide).
• Concentrated H2SO4 Reaction: Used for alcohol preparation; the reaction mixture darkens and changes color upon heating.

Expected Experiment Results

• S1: Acetone and ethanol should dissolve due to their small size and polar nature.
• S2: Sucrose is insoluble in ether due to many hydrophilic functional groups.
• A1/A2: Weak acids like benzoic acid (pKa = 4.2) react with strong bases, whereas weaker acids like phenol (pKa = 9.9) do not.
• B Class: Aniline reacts with HCl to form water-soluble ammonium salt.
• M Class: Benzamide is included, with benzaldehyde and benzyl alcohol typically showing moderate solubility.
• I Class: Saturated hydrocarbons like hexane demonstrate low solubility.

Safety Notes

• Conduct reactions under fume hoods when handling toxic substances, particularly bromine.
• Use appropriate protective equipment to prevent skin and respiratory irritation from chemicals.

Bonus Note

• Phenol solutions should be tested in pure solid form for accurate results.

This quiz covers key experiments and concepts from the MT-MLS104L Inorganic and Organic Chemistry Laboratory course. It includes questions on the solubility of organic compounds, reactions of hydrocarbons, alkyl halides, and naming formula writing of inorganic compounds. Prepare yourself to apply your knowledge and succeed in your preliminary lab exam.