MT-MLS104L Inorganic and Organic Chemistry Lab

Questions and Answers

What is one reason sucrose is not soluble in ether?

It forms insoluble salts in ether.

It contains hydrophilic functional groups. (correct)

It has a high molecular weight.

It is an acidic compound.

How do benzoic acid and phenol differ in their acidity?

Benzoic acid is a weak acid and phenol is a strong acid.

Benzoic acid has a higher pKa than phenol.

Both have the same strength as acids.

Phenol is a weaker acid than benzoic acid. (correct)

What type of salt do amines form when they react with acids?

Neutral salts.

Insoluble salts.

Salts that do not dissolve in water.

Water-soluble ammonium salts. (correct)

Why will weaker acids, like phenols, not react with weak bases like NaHCO3?

They require a stronger base to react. Signup and view all the answers

Which of the following represents saturated hydrocarbons?

Compounds with carbon-carbon single bonds. Signup and view all the answers

What type of compounds does the ethanolic silver nitrate test specifically target?

2º and 3º alkyl halides Signup and view all the answers

What color indicates the presence of silver chloride in the ethanolic silver nitrate test?

White Signup and view all the answers

Which reagent is used in the ethanolic silver nitrate test?

0.1 M silver nitrate in ethanol Signup and view all the answers

How does the solution change in color when toluene is heated with concentrated sulfuric acid?

Turns yellow then amber Signup and view all the answers

What does a positive result in the bromine test indicate?

Presence of unsaturation Signup and view all the answers

What color indicates the presence of silver bromide in the ethanolic silver nitrate test?

Pale yellow Signup and view all the answers

Which of the following tests is NOT specifically used to detect halides?

Conc. H2SO4 test Signup and view all the answers

What does a negative result in the ethanolic silver nitrate test suggest?

No halides present Signup and view all the answers

What is the primary reason that ionic compounds are generally soluble in water?

Like dissolves like, and water is polar. Signup and view all the answers

Which characteristic makes a molecule more likely to dissolve in water?

Ability to form hydrogen bonds with water. Signup and view all the answers

What effect does an increase in molecular weight typically have on the solubility of a solid compound?

It decreases solubility due to increased intermolecular forces. Signup and view all the answers

Which type of compounds is known to be soluble in nonpolar solvents?

Nonpolar compounds. Signup and view all the answers

What is the overarching rule concerning the solubility of compounds?

'Like dissolves like' is the key principle of solubility. Signup and view all the answers

How does branching in the structure of a compound affect its solubility?

Branched compounds are generally more soluble than their straight-chain counterparts. Signup and view all the answers

What distinguishes water-soluble neutral molecules from non-soluble ones?

They contain many oxygen or nitrogen atoms capable of hydrogen bonding. Signup and view all the answers

What is a defining characteristics of a water-soluble compound?

It can form hydrogen bonds with water. Signup and view all the answers

What is the main purpose of the bromine test?

To test for the presence of unsaturated hydrocarbons Signup and view all the answers

What color indicates a positive result for the bromine test?

Orange-red Signup and view all the answers

What reagent is used in Baeyer's test?

Alkaline KMnO4 Signup and view all the answers

What confirms a successful reaction in Baeyer's test?

Disappearance of the purple color and formation of a brown precipitate Signup and view all the answers

Which of the following statements about the bromine test is correct?

Bromine water does not interact with saturated compounds. Signup and view all the answers

What precautions should be taken when performing the bromine test?

Use a ventilated area due to toxic fumes. Signup and view all the answers

Which of the following will react with bromine in the addition of bromine test?

Cyclohexene Signup and view all the answers

What happens to the purple color of alkaline KMnO4 during a successful Baeyer's test?

It disappears. Signup and view all the answers

What is the primary benefit of branching in a molecule related to solubility?

It reduces the size of the molecule, aiding solvation. Signup and view all the answers

Which solvent is commonly used in solubility tests?

5% HCl Signup and view all the answers

Which category does not belong in the S1 classification of compounds based on solubility?

Cyclohexane Signup and view all the answers

Which of the following compounds is classified as A2 based on solubility?

Phenols Signup and view all the answers

What characteristic defines A1 compounds in solubility classification?

They include strong organic acids with more than six carbons. Signup and view all the answers

Which of the following is classified under the N category based on solubility?

Ethers with five to nine carbons Signup and view all the answers

Which compound is an example of S2 classification based on solubility?

Amino acids Signup and view all the answers

What type of compounds fall under the B classification of solubility?

Aliphatic amines with eight or more carbons Signup and view all the answers

Which of the following solvents is least likely to effectively solvate small polar molecules?

Diethyl ether Signup and view all the answers

Which of the following would not be expected to exhibit significant solubility in water?

Hexane Signup and view all the answers

Study Notes

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.

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Description

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.