Semipolar Solvents and Types of Solutions in Pharmaceutical Chemistry
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Questions and Answers

What role can semipolar solvents, like ketones, play in solutions?

  • Decreasing the solubility of polar liquids in nonpolar liquids
  • Creating a barrier between polar and nonpolar molecules
  • Inducing polarity in nonpolar solvent molecules (correct)
  • Enhancing the miscibility of nonpolar and polar liquids

    • Which type of solutions are of pharmaceutical importance according to the text?

  • Gases in gases
  • Liquids in liquids (correct)
  • Solids in gases
  • Liquids in solids

    • What does Henry's law state about the relationship between the concentration of dissolved gas and the partial pressure?

  • The concentration is inversely proportional to the partial pressure
  • There is no relationship between concentration and partial pressure
  • The concentration remains constant regardless of the partial pressure
  • The concentration is directly proportional to the partial pressure (correct)

    • How does the solubility of a gas in a liquid change with temperature?

    <p>Increases with higher temperature</p> Signup and view all the answers

    What factor does the solubility of a gas in a liquid depend on according to the text?

    <p>Pressure, temperature, salts, and chemical reactions</p> Signup and view all the answers

    What is the main purpose of semipolar solvents like acetone in solubility processes?

    <p>Enhancing miscibility between polar and nonpolar liquids</p> Signup and view all the answers

    What happens to the solubility of gases as temperature increases?

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

    Why should a container of gaseous solution or high vapor pressure liquid be immersed in ice before opening in warm climates?

    <p>To reduce the temperature and pressure of the gas</p> Signup and view all the answers

    What effect does adding electrolytes like NaCl to gaseous solutions have?

    <p>Increases liberation of gases</p> Signup and view all the answers

    What defines an ideal solution according to Raoult's law?

    <p>Adhesive forces are equal to cohesive forces</p> Signup and view all the answers

    What is a saturated solution?

    <p>A solution with dissolved solute in equilibrium with the solid phase</p> Signup and view all the answers

    In real solutions, when do components not obey Raoult's law?

    <p>When they are of two types</p> Signup and view all the answers

    How is solubility defined in quantitative terms?

    <p>As the concentration of solute in a saturated solution at a certain temperature</p> Signup and view all the answers

    Why do electrolytes like NaCl induce liberation of gases from gaseous solutions?

    <p>Because the gas molecules are highly attracted to the electrolyte ions</p> Signup and view all the answers

    What is an unsaturated solution?

    <p>A solution containing dissolved solute below saturation point at a definite temperature</p> Signup and view all the answers

    What happens in a supersaturated solution?

    <p>More solute is present than it would normally contain at that temperature</p> Signup and view all the answers

    In the example given, why does glucose precipitate from the solution when cooled?

    <p>Because the system has a higher amount of dissolved glucose than predicted by the solubility limit</p> Signup and view all the answers

    What distinguishes a supersaturated solution from a saturated one?

    <p>More solute present than it would normally contain at a specific temperature</p> Signup and view all the answers

    What is the guiding principle for selecting a suitable solvent?

    <p>Like dissolves like</p> Signup and view all the answers

    Which type of solutes dissolve best in nonpolar solvents?

    <p>Nonpolar solutes</p> Signup and view all the answers

    How does branching in the carbon chain of aliphatic alcohols affect water solubility?

    <p>It increases water solubility</p> Signup and view all the answers

    What feature of polar solvents plays a role in reducing the force of attraction between oppositely charged ions in crystals?

    <p>Dielectric constant</p> Signup and view all the answers

    Which type of compounds are generally water-soluble due to the presence of additional polar groups?

    <p>Polyhydroxy compounds</p> Signup and view all the answers

    In which types of alcohols does the presence of straight chains with more than 5 carbon atoms lead to slight solubility in water?

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

    What is the formula for the distribution coefficient (K) used to determine the efficiency of extracting a compound from a solvent?

    <p>K = Wn / (KV1 + V2)</p> Signup and view all the answers

    According to the equation provided, when is an extraction most efficient?

    <p>When n is large and V2 is small</p> Signup and view all the answers

    What is meant by 'weight in grams of a solute is extracted repeatedly' in the context of the provided equation?

    <p>The weight of the solute extracted multiple times</p> Signup and view all the answers

    In the given example, what does K = 0.012 represent?

    <p>The distribution coefficient for iodine between water and carbon tetrachloride</p> Signup and view all the answers

    What does 'CH2O/CCCl4' represent in the context of the given example?

    <p>The distribution coefficient between two solvents</p> Signup and view all the answers

    What impact does increasing 'n', the number of extraction repetitions, generally have on extraction efficiency?

    <p>Increases efficiency</p> Signup and view all the answers

    What does the equation for an ideal solution of a solid in a liquid indicate about solubility at temperatures above the melting point?

    <p>Solubility does not apply above the melting point</p> Signup and view all the answers

    In an ideal solution, what state is the solute in when temperatures are above its melting point?

    <p>Liquid state</p> Signup and view all the answers

    What happens to the solute's solubility as the temperature of the solution increases according to the provided example?

    <p>Solubility increases</p> Signup and view all the answers

    What is the effect on solubility when the temperature of a solution is lowered?

    <p>Solubility decreases</p> Signup and view all the answers

    What does the term 'miscible in all proportions' in the context of an ideal solution imply?

    <p>Solute mixes uniformly with solvent regardless of quantity</p> Signup and view all the answers

    What is the significance of R=1.987 Cal/mole.k in determining solubility according to the provided equation?

    <p>It represents a constant in the solubility equation</p> Signup and view all the answers

    Which indomethacin polymorph has the lowest melting point?

    <p>Polymorph VII</p> Signup and view all the answers

    Based on the solubility ranking given in the text, which property is more useful in ordering the solubility of indomethacin polymorphs?

    <p>Molar heat of fusion (∆Hf)</p> Signup and view all the answers

    What is the ideal mole fraction solubility of polymorph I at 25°C based on the provided data?

    <p>$0.0069$</p> Signup and view all the answers

    In non-ideal solutions, what should be considered, according to the text?

    <p>Electrostatic and intermolecular forces</p> Signup and view all the answers

    What factor determines the solubility ranking of the indomethacin polymorphs?

    <p>Molar heat of fusion</p> Signup and view all the answers

    If polymorph II has a molar heat of fusion of 9700 cal/mole, what is its ideal mole fraction solubility?

    <p>$0.0073$</p> Signup and view all the answers

    In the context of solubility expressions, what does the activity coefficient measure?

    <p>The deviation from ideal behavior in a solution</p> Signup and view all the answers

    Which statement best describes the relationship between an ideal solution and its activity coefficient (ɣ2)?

    <p>As a real solution becomes more ideal, ɣ2 approaches unity.</p> Signup and view all the answers

    What happens to the mole fraction solubility of a solute as the solution becomes more ideal?

    <p>Decreases as the activity coefficient approaches unity</p> Signup and view all the answers

    How is the mole fraction solubility expressed in a non-ideal solution when converted to logarithmic form?

    <p>$log X2 = log \gamma_2 - log 2.303RTT_0$</p> Signup and view all the answers

    What does the term 'solubility in an ideal solution' refer to in the provided text?

    <p>The solubility of a solute when the activity coefficient is equal to 1</p> Signup and view all the answers

    What is the significance of the equation $log a_2 = -log \lambda = 2.303RTT_i$ in solubility calculations?

    <p>It demonstrates how ideal solutions differ from non-ideal solutions</p> Signup and view all the answers

    What happens to the solubility of Na2SO4.10H2O as the temperature increases above 32°C?

    <p>It decreases</p> Signup and view all the answers

    How does the solubility of sodium chloride change with a temperature increase?

    <p>It remains the same</p> Signup and view all the answers

    What happens to weak acids when pH is lowered to below 9.3?

    <p>They precipitate from the solution</p> Signup and view all the answers

    How do weak bases behave in the presence of stronger basic substances?

    <p>They precipitate as free bases</p> Signup and view all the answers

    Which process is exothermic for Na2SO4 above 32°C?

    <p>Precipitation of Na2SO4</p> Signup and view all the answers

    Why do alkaloidal salts like atropine sulfate begin to precipitate when the pH is elevated?

    <p>They precipitate as free bases</p> Signup and view all the answers

    What is the special constant used to describe the solubility of slightly soluble electrolytes?

    <p>Solubility product (Ksp)</p> Signup and view all the answers

    In the equilibrium expression [Ag+][Cl-] = Ksp, why are concentrations used instead of activities?

    <p>Solid phase concentration is essentially constant</p> Signup and view all the answers

    What does raising the concentration of each ion to a power equal to the number of ions appearing in the formula indicate?

    <p>Equilibrium expression</p> Signup and view all the answers

    In the given example, what does the measured solubility of silver chloride of 1.12 x 10^-5 mole/liter at 20°C represent?

    <p>Concentration of solute</p> Signup and view all the answers

    How does the equilibrium expression for aluminum hydroxide, Al(OH)3, differ from that of silver chloride, AgCl?

    <p>[Al3+][OH-] = Ksp vs. [Ag+][Cl-] = Ksp</p> Signup and view all the answers

    Why are concentrations used instead of activities in the equilibrium expressions for slightly soluble electrolytes?

    <p>To maintain constant ionic strength</p> Signup and view all the answers

    In an ideal solution of solids, what factor does NOT affect the solubility of a solid?

    <p>Nature of the solvent</p> Signup and view all the answers

    What is the term used to describe the increase in mutual solubility of two partially miscible solvents by another agent?

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

    In a real (non-ideal) solution of solids, what is the relationship between the heat of solution and the heat of fusion?

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

    If a material is soluble in both liquids in a liquid pair, how is the mutual solubility of the liquids affected?

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

    What action on a phenol-water system leads to an increase in their mutual solubility?

    <p>Addition of succinic acid</p> Signup and view all the answers

    What is meant by 'blending' when discussing the solubility of two partially miscible solvents?

    <p>Increasing the miscibility</p> Signup and view all the answers

    What does the rational activity coefficient (ɣ2) represent in the formula a2 = X2ɣ2?

    <p>Correction factor for non-ideal behavior</p> Signup and view all the answers

    In an ideal solution, what is the value of the activity coefficient (ɣ2)?

    <p>1</p> Signup and view all the answers

    What does the equation 𝜟𝑯𝒇 𝑻𝟎 − 𝑻 𝒊 𝐥𝐨𝐠 a 𝟐 = −𝐥𝐨𝐠𝝌 = 𝟐 𝟐.𝟑𝟎𝟑𝑹 𝑻𝑻𝟎 imply about the solubility of a solute in a non-ideal solution?

    <p>Solubility decreases with increasing temperature</p> Signup and view all the answers

    What happens to the mole fraction solubility of a solute as the solution becomes more ideal?

    <p>Approaches zero</p> Signup and view all the answers

    How does the mole fraction solubility in various solvents change as the rational activity coefficient (ɣ2) approaches unity?

    <p>Remains constant</p> Signup and view all the answers

    What is the significance of the ideal solubility equation a2=𝝌 in an ideal solution?

    <p>Demonstrates the concept of an ideal solution</p> Signup and view all the answers

    What is the qualitative definition of solubility as provided in the text?

    <p>The interaction of substances to form a homogeneous dispersion</p> Signup and view all the answers

    In the example given, why does glucose sometimes take a while to crystallize after cooling the solution?

    <p>It takes time for the molecules to find their solid structure positions</p> Signup and view all the answers

    What is a supersaturated solution, according to the text?

    <p>A solution with more dissolved solute than normal at a certain temperature</p> Signup and view all the answers

    What happens if a solution is cooled to 25°C and 9 g of glucose precipitates, but the system has 100 g of dissolved glucose?

    <p>The system is supersaturated with glucose</p> Signup and view all the answers

    What phenomenon occurs when a solution contains less dissolved solute than needed for complete saturation at a specific temperature?

    <p>Unsaturated or subsaturated solution</p> Signup and view all the answers

    If a solution contains only the necessary amount of solute to be in equilibrium with the solid phase at a given temperature, what type of solution is it?

    <p>Saturated solution</p> Signup and view all the answers

    In the context of the provided text, what does the term 'C' represent in the equation C = (Kq+1 + Ka/[H3O+])[HA]w?

    <p>Total concentration of benzoic acid needed to preserve an oil-water mixture</p> Signup and view all the answers

    What is the purpose of the dissociation constant Ka in the context of the mentioned equations?

    <p>To measure the concentration of undissociated acid in the aqueous phase</p> Signup and view all the answers

    What does the volume ratio 'q' represent in the equation C = (Kq+1 + Ka/[H3O+])[HA]w?

    <p>Volume ratio of peanut oil to water</p> Signup and view all the answers

    Based on the text, what does 'Ka' being 6.4 x 10^-5 indicate about the acid in water?

    <p>Weak acidic properties of the acid</p> Signup and view all the answers

    How does the partition coefficient 'K' influence the distribution of benzoic acid between peanut oil and water?

    <p>Affects how much benzoic acid remains in the water phase</p> Signup and view all the answers

    What role does the total concentration 'C' play in achieving a final specified concentration [HA]w of undissociated acid in the aqueous phase?

    <p>Calculates the amount needed to maintain undissociated acid at a specific pH</p> Signup and view all the answers

    What happens to the solubility of a gas in a liquid when the pressure above the solution decreases, as explained in the text?

    <p>The gas escapes from the solution.</p> Signup and view all the answers

    In the context of solubility and distribution, what does the term 'effervescent solutions' refer to?

    <p>Solutions that contain a gas under pressure</p> Signup and view all the answers

    What phenomenon occurs when the stopper of a container with an effervescent solution is removed?

    <p>The gas escapes violently.</p> Signup and view all the answers

    How does the temperature affect the solubility of a gas in a liquid, based on the information provided?

    <p>As temperature increases, gas solubility decreases.</p> Signup and view all the answers

    What happens to the solubility of a gas in a liquid when the total pressure above the mixture is decreased?

    <p>The gas escapes from the solution.</p> Signup and view all the answers

    Based on the given examples and information, what factor primarily determines the amount of a gas that can be dissolved in a liquid?

    <p>The partial pressure of the undissolved gas above the solution</p> Signup and view all the answers

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