Acids and Bases
If a concentrated solution of potassium hydrogen sulfate (KHSO4) gives up a proton, what is the primary effect on pH of the solution?
The salt K2SO4 is formed, leading to a decrease in solubility of other ions present in the solution.
The pH of the solution would increase as the solution becomes less acidic.
The pH of the solution would decrease as it becomes more alkaline.
The formation of hydrogen peroxide (H2O2) leads to an oxidative environment within the solution.
Which of the following is true about NH3 and NaOH?
It is a buffer solution because NH3 is a weak acid and NaOH is its conjugate base
It is a buffer solution because NaOH is a strong base and NH3 is a strong acid
It is not a buffer solution NaOH is a strong base
It is not a buffer solution because NH3 is a weak acid and NaOH is not its conjugate base
When making homemade salad dressing by mixing vinegar and oil, why does adding baking soda help emulsify and stabilize the mixture?
Baking soda breaks down oil molecules making them easier to mix with vinegar without forming buffers.
Baking soda reacts with vinegar to form a buffer that stabilizes the mixture's pH, aiding emulsification.
Baking soda acts solely as a thickening agent and does not interact chemically with vinegar or oil regarding buffers.
Baking soda increases oil solubility in vinegar purely through physical agitation without involving any buffer action.
What amount of solid sodium acetate is needed to prepare a buffer of pH 5.0 from 1.00 L of 0.10 M acetic acid (pKa = 4.75; molar mass of sodium acetate = 80.0343 g/mol)?
0.1778 mol
14.58 g
0.18 mol
15 g
Which pair of substances below will form an effective phosphate buffer at physiological pH?
Sodium chloride (NaCl) and potassium chloride (KCl)
Dihydrogen phosphate (H₂PO₄⁻) and hydrogen phosphate (HPO₄²⁻)
Carbon dioxide and carbonic acid
Hydrochloric Acid (HCI) and sodium chloride (NaCl)
Considering periodic trends, which element would exhibit the least metallic character?
Sodium (Na)
Potassium (K)
Fluorine (F)
Lithium (Li)
In the context of buffers, what does pKa represent?
The optimal temperature at which an enzyme works best in buffered solutions.
The exact midpoint on a titration curve where all reactants are consumed.
The negative logarithm of the Ka value for any strong acid.
The pH at which half the molecules are dissociated into their respective ions for a particular weak acid.

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If equal molar amounts of NH3 and NH4+ are mixed together, which species predominates after addition of a strong base?
Ammonia (NH3) predominates due to the removal of H+ ions by the strong base.
Ammonium ion (NH4+) predominates because it is more stable than NH3 in basic conditions.
Both ammonia and ammonium ion concentrations remain equal as there's no reaction with the base.
Neither species predominate as they react with each other forming N2 gas and water instead.
Why do buffers work best close to their pKa?
They require less activation energy for reactions occurring near their pKa/pH.
They work equally well at any pH range since they can adjust rapidly.
Buffers stabilize pH most effectively around their pKa because that's when there is significant presence of both species (acid/base) required for neutralizing added acids/bases.
They lose their ability to resist changes in temperature rather than acidity/basicity.
Which of the following is NOT an application of a buffer solution?
Keep the pH of blood at a constant value
Provide a wide range of pH for biochemical processes to function
Prevent solutions from becoming too acidic during fermentation
Maintain an acidic pH in shampoos