Non-Aqueous Titration Quiz and Flashcards

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Questions and Answers

Match the following solvents with their characteristic:

Aprotic solvents = Do not accept or donate H+ Amphiprotic solvents = Act as acids or bases Protogenic solvents = Have a leveling effect on weak bases Protophillic solvents = Have a leveling effect on weak acids

Match the following types of solvents with their examples:

Aprotic solvents = Benzene Amphiprotic solvents = Methanol Protogenic solvents = Hydrochloric acid Protophillic solvents = Liquid ammonia

Match the following reagents with their uses in non-aqueous titration:

Glacial acetic acid = Solvent for titrating basic substances Acetous perchloric acid = Titrant for titrating basic substances Crystal violet = Indicator for titrating basic substances Acetic anhydride = Reagent for acetylating amines

Match the following reactions with their equations:

Primary amine with acetous perchloric acid = RNH2 + HClO4 → RNH3+ + ClO4- Secondary amine with acetous perchloric acid = R2NH + HClO4 → R2NH2+ + ClO4- Tertiary amine with acetous perchloric acid = R3N + HClO4 → R3NH+ + ClO4- Primary amine with acetic anhydride = RNH2 + (CH3CO)2O → RNHCOCH3 + CH3COOH Signup and view all the answers

Match the following applications with their descriptions:

Determination of basic substances = Titrating amines with acetous perchloric acid Determination of tertiary amine only = Acetylating amines with acetic anhydride Non-aqueous titration = Titration using solvents other than water Dielectric constant = Ability to separate positively and negatively charged ions Signup and view all the answers

Match the following solvents with their dielectric constants (D):

Water (H2O) = D = high Ethanol = D = low Glacial acetic acid = D = high Hexane = D = low Signup and view all the answers

Match the following indicators with their color changes:

Crystal violet = Violet (basic) to bluish green (acidic) Phenolphthalein = Colorless (acidic) to pink (basic) Methyl orange = Yellow (acidic) to red (basic) Bromothymol blue = Yellow (acidic) to blue (basic) Signup and view all the answers

Match the following amines with their reactions:

Primary amine = RNH2 + HClO4 → RNH3+ + ClO4- Secondary amine = R2NH + HClO4 → R2NH2+ + ClO4- Tertiary amine = R3N + HClO4 → R3NH+ + ClO4- Mixture of amines = Acetylated with acetic anhydride Signup and view all the answers

Match the following properties of solvents in non-aqueous titrations with their descriptions:

Relative acidity and basicity = The ability of a solvent to increase the strength of weak acids or weak bases Levelling effect = The ability of a solvent to differentiate between the strength of acids or bases Differentiating effect = The ability of a solvent to increase the strength of weak acids or weak bases Autoprotolysis = The ability of a solvent to behave as an acid or a base relative to the substance Signup and view all the answers

Match the following substances with their behavior in a particular solvent:

Potassium acid phthalate = Acts as a base in glacial acetic acid Acetic acid = Acts as a base in pyridine Amines = Behave as strong acids in glacial acetic acid Weak carboxylic acids = Behave as weak acids in liquid ammonia Signup and view all the answers

Match the following solvents with their effect on weak acids or weak bases:

Glacial acetic acid = Increases the strength of weak acids Liquid ammonia = Increases the strength of weak bases Pyridine = Differentiates between the strength of mineral acids Water = Has a levelling effect on weak acids and weak bases Signup and view all the answers

Match the following effects of solvents with their examples:

Levelling effect = Acetic acid behaving as a base in perchloric acid Differentiating effect = Glacial acetic acid differentiating between the strength of mineral acids Relative acidity and basicity = Amines behaving as strong bases in glacial acetic acid Autoprotolysis = Glacial acetic acid having a levelling effect on weak bases Signup and view all the answers

Match the following equations with their descriptions:

HA + HA ↔ [A- HAH +] ↔ A- + H2A+ = Autoprotolysis reaction of a solvent Ks = [A-] [H2A+] = Equation for the levelling effect of a solvent A- + H2A+ → HA + HA = Reverse reaction of autoprotolysis Ks = [H2A+] / [A-] = Equation for the differentiating effect of a solvent Signup and view all the answers

Match the following solvents with their characteristics:

Glacial acetic acid = Basic solvent Liquid ammonia = Acidic solvent Pyridine = Basic solvent Water = Neutral solvent Signup and view all the answers

Match the following statements with their correctness:

Glacial acetic acid has a levelling effect on weak acids = False Liquid ammonia has a differentiating effect on weak bases = False Acetic acid behaves as a base in pyridine = True Water has a levelling effect on weak acids and weak bases = False Signup and view all the answers

Match the following terms with their definitions:

Autoprotolysis = The ability of a solvent to differentiate between the strength of acids or bases Levelling effect = The ability of a solvent to behave as an acid or a base relative to the substance Differentiating effect = The self-dissociation reaction of a solvent Relative acidity and basicity = The ability of a solvent to increase the strength of weak acids or weak bases Signup and view all the answers

Study Notes

Neutralization Reactions in Non-Aqueous Medium

Neutralization reactions in non-aqueous medium involve titration in a medium free from water, mainly used for determining weak acids and weak bases.

Properties of Solvents in Non-Aqueous Titrations

Relative acidity and basicity of a substance are relative to the solvent.
A substance behaves as an acid when dissolved in a less acidic solvent and as a base when dissolved in a more acidic solvent.

Levelling Effect

Ability of solvent to increase the strength of weak acids or weak bases to reach the level of strong acid or base respectively.
Acidic solvents have levelling effect on weak bases, and basic solvents have levelling effect on weak acids.

Differentiating Effect

Ability of solvent to differentiate between the strength of acids or bases.
Glacial acetic acid differentiates between the strength of mineral acids.

Autoprotolysis (Ks)

Self-dissociation reaction of solvent.
Good solvent should have small Ks to minimize the production of ionic species that compete with the substance to be determined.

Dielectric Constant (D)

Ability to separate positively charged ions from negatively charged ions.
Good solvent should have high D to ensure completeness of reactions.

Types of Solvents Used in Non-Aqueous Titrations

Aprotic solvents: neutral, inert, do not accept or donate H+, have no autoprotolytic and no levelling effect. Examples: Hydrocarbons, Benzene, CHCl3, CCl4, and nitrobenzene.
Amphiprotic solvents: act as acids or bases, may donate or accept H+.

Applications of Non-Aqueous Titration

Determination of basic substances: use glacial acetic acid as solvent and acetous perchloric acid as titrant.
Determination of tertiary amine only: sample is refluxed with acetic anhydride to acetylate primary and secondary amines.

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Description

This quiz covers neutralization reactions in non-aqueous mediums, focusing on titration methods for determining weak acids and bases in solvents other than water.