Acid and Base Exercise \(\PageIndex{1}\) According to the Arrhenius definition, a base produces ___________ ion in aqueous solution. Exercise \(\PageIndex{2}\) According to the Arrhenius definition, an acid produces ___________ ion in aqueous solution. Exercise \(\PageIndex{3}\) What common ion do \(\ce{HF}\), \(\ce{HCl}\), \(\ce{HBr}\) and \(\ce{HI}\) produce when dissolved in an aqueous solution? a. Chloride ions b. Fluoride ions c. Iodide ions d. Hydronium ions e. Hydroxide ions f. Water ions Exercise \(\PageIndex{4}\) Match the acid formula with its correct name from the list: sulfuric acid, perchloric acid, nitric acid, hydroiodic acid. a. \(\ce{H2SO4}\) b. \(\ce{HNO3}\) c. \(\ce{HI}\) d. \(\ce{HClO3}\) Exercise \(\PageIndex{5}\) Match the acid formula with its correct name from the list: sulfurous acid, periodic acid, nitrous acid, hydrochloric acid. a. \(\ce{HCl}\) b. \(\ce{HNO2}\) c. \(\ce{H2SO3}\) d. \(\ce{HIO4}\) Exercise \(\PageIndex{6}\) The name given to an aqueous solution of \(\ce{HNO3}\) is: a. nitric acid b. nitrous acid c. hydrogen nitrate d. hydronitrogen acid e. hyponitric acid Exercise \(\PageIndex{7}\) Which of the following is not a characteristic of a base? a. Has a bitter taste b. Produces \(\ce{H^+}\) in water c. Tastes chalky d. Soapy, slippery Exercise \(\PageIndex{8}\) Which of the following is not a characteristic of an acid? a. has a sour taste b. produces \(\ce{OH^-}\) in aqueous solutions c. is an electrolyte d. produces \(\ce{H^+}\) in aqueous solutions Exercise \(\PageIndex{9}\) When \(\ce{HCl}\) is dissolved in water, the following reaction occurs. According to Arrhenius, why is \(\ce{HCl}\) considered and acid? \[\ce{HCl} (g) + \ce{H2O} (l) \rightarrow \ce{H3O^+} (aq) + \ce{Cl^-} (aq) \nonumber\] a. It is soluble in water b. It produces \(\ce{H^+}\) or \(\ce{H3O^+}\) when dissolved in water c. It accepts \(\ce{H^+}\) or \(\ce{H3O^+}\) when dissolved in water d. It produces \(\ce{Cl^-}\) in solution Exercise \(\PageIndex{10}\) According to Arrhenius, what common product do all bases produce when dissolved in water? Exercise \(\PageIndex{11}\) Classify the following compounds as Arrhenius acids and bases a. \(\ce{NaOH}\) b. \(\ce{BaOH}\) c. \(\ce{HBr}\) d. \(\ce{HNO3}\) e. \(\ce{H­_2CO3}\) f. \(\ce{NH3}\) g. \(\ce{HF}\) Exercise \(\PageIndex{12}\) Identify each of the following as an acid or a base, and give its name: a. \(\ce{H3PO4}\), ingredient in soft drinks b. \(\ce{NaOH}\), ingredient in oven cleaner c. Magnesium hydroxide, ingredient in antacids d. \(\ce{HBr}\), used industrially to prepare bromide compounds Bronsted-Lowry Acids and Bases Exercise \(\PageIndex{13}\) In the reaction shown, Identify each of compounds as either Bronsted Lowry acid (A), base (B), conjugate acid (CA), or conjugate base (CB). \[2\ce{HCl} (aq) + \ce{Mg(OH)2} (s) \rightarrow \ce{MgCl2} (aq) + 2\ce{H2O} (l) \nonumber\] a. \(\ce{HCl}\): __________ b. \(\ce{Mg(OH)2}\): __________ c. \(\ce{MgCl2}\): __________ d. \(\ce{H2O}\): __________ Exercise \(\PageIndex{14}\) Which of the following is an incorrect conjugate acid/base pair? a. \(\ce{HBr}\)/\(\ce{Br^-}\) b. \(\ce{H2S}\)/\(\ce{S2^{-}}\) c. \(\ce{HNO2}\)/\(\ce{NO2^{-}}\) d. \(\ce{NH4^+}\)/\(\ce{NH3}\) e. \(\ce{H2O}\)/\(\ce{OH^-}\) Exercise \(\PageIndex{15}\) According to Bronsted-Lowry, an acid is a _________ ___________ a. proton donor b. proton acceptor c. water soluble d. poisonous substance Exercise \(\PageIndex{16}\) What is the conjugate base of nitric acid, \(\ce{HNO3}\)? a. \(\ce{HNO3}\) b. \(\ce{H2NO3^+}\) c. \(\ce{NO3^-}\) d. \(\ce{H3O^+}\) Exercise \(\PageIndex{17}\) What is the conjugate acid of \(\ce{NO3^-}\)? a. \(\ce{HNO3}\) b. \(\ce{H2NO3^+}\) c. \(\ce{NO3^-}\) d. \(\ce{H3O^+}\) Exercise \(\PageIndex{18}\) What is the conjugate base of water, \(\ce{H2O}\)? a. \(\ce{H2O}\) b. \(\ce{OH^-}\) c. \(\ce{H2O^+}\) d. \(\ce{H3O^+}\) Exercise \(\PageIndex{19}\) What is the conjugate base of hydrochloric acid, \(\ce{HCl}\)? a. \(\ce{HCl}\) b. \(\ce{H^+}\) c. \(\ce{Cl^-}\) d. \(\ce{H2Cl^+}\) Exercise \(\PageIndex{20}\) What is the conjugate acid of water, \(\ce{H2O}\)? a. \(\ce{H2O}\) b. \(\ce{OH^-}\) c. \(\ce{H2O^+}\) d. \(\ce{H3O^+}\) Exercise \(\PageIndex{21}\) In each of the following equations, identify the reactant that is a Brønsted–Lowry acid and the reactant that is a Brønsted–Lowry base: a. \(\ce{HBr} (aq) + \ce{H2O} (l) \rightarrow \ce{H3O^+} (aq) + \ce{Br^-} (aq) \) b. \(\ce{CN^-} (aq) + \ce{H2O} (l) \rightleftarrows \ce{HCN} (aq) + \ce{OH^-} (aq) \) Exercise \(\PageIndex{22}\) Identify the conjugate acid–base pairs in each of the following reactions: a. \(\ce{HCN} (aq) + \ce{SO4^{2-}} (aq) \rightleftarrows \ce{CN^-} (aq) + \ce{HSO4^-} (aq) \) b. \(\ce{H2O} (l) + \ce{S^{2-}} (aq) \rightleftarrows \ce{OH^-} (aq) + \ce{HS^-} (aq) \) Strengths of Acids and Bases Exercise \(\PageIndex{23}\) List the following acids in order from weakest to strongest based on the information in the table provided. a. \(\ce{H3PO4}\) b. \(\ce{HCN}\) c. \(\ce{H3O^+}\) d. \(\ce{HNO2}\) e. \(\ce{H2CO3}\) Acid Unnamed: 1 Conjugate Base Unnamed: 3 Strong Acids (Acid strength increases \(\uparrow\)) Weak Bases (Base strength increases \(\downarrow\)) Hydroiodic acid \(\ce{HI}\) \(\ce{I^{-}}\) Iodide ion Hydrobromic acid \(\ce{HBr}\) \(\ce{Br^{-}}\) Bromide ion Perchloric acid \(\ce{HClO4}\) \(\ce{ClO4^{-}}\) Perchlorate ion Hydrochloric acid \(\ce{HCl}\) \(\ce{Cl^{-}}\) Chloride ion Sulfuric acid \(\ce{H2SO4}\) \(\ce{HSO4^{-}}\) Hydrogen sulfate ion Nitric acid \(\ce{HNO3}\) \(\ce{NO3^{-}}\) Nitrate ion Hydronium ion \(\ce{H3O^+}\) \(\ce{H2O}\) Water Weak Acids (Acid strength increases \(\uparrow\)) Strong Bases (Base strength increases \(\downarrow\)) Hydrogen sulfate ion \(\ce{HSO4^-}\) \(\ce{SO4^{2-}}\) Sulfate ion Phosphoric acid \(\ce{H3PO4}\) \(\ce{H2PO4^{-}}\) Dihydrogen phosphate ion Nitrous acid \(\ce{HNO2}\) \(\ce{NO2^{-}}\) Nitrite ion Hydrofluoric acid \(\ce{HF}\) \(\ce{F^{-}}\) Flouride ion Acetic acid \(\ce{HC2H3O2}\) \(\ce{C2H3O2^{-}}\) Acetate ion Carbonic acid \(\ce{H2CO3}\) \(\ce{HCO3^{-}}\) Bicarbonate ion Hydrosulfuric acid \(\ce{H2S}\) \(\ce{HS^{-}}\) Hydrogen sulfide ion Dihydrogen phosphate ion \(\ce{H2PO4^-}\) \(\ce{HPO4^{2-}}\) Hydrogen phosphate ion Ammonium ion \(\ce{NH4^+}\) \(\ce{NH3}\) Ammonia Hydrocyanic acid \(\ce{HCN}\) \(\ce{CN^{-}}\) Cyanide ion Bicarbonate ion \(\ce{HCO3^-}\) \(\ce{CO3^{2-}}\) Carbonate ion Methylammonium ion \(\ce{CH3-NH3^+}\) \(\ce{CH3-NH2}\) Methylamine Hydrogen phosphate ion \(\ce{HPO4^{2-}}\) \(\ce{PO4^{3-}}\) Phosphate ion Water \(\ce{H2O}\) \(\ce{OH^{-}}\) Hydroxide ion Exercise \(\PageIndex{24}\) Rank the following acids from strongest (3) to weakest (1). a. \(\ce{HC2H3O2}\) \(K_a = 1.8 \times 10^{-5}\) b. \(\ce{HF}\) \(K_a = 7.2 \times 10^{-4}\) c. \(\ce{H2CO3}\) \(K_a = 4.3 \times 10^{-7}\) Exercise \(\PageIndex{25}\) Which of the following statements are true about a strong acid? a. Dissociates partially in solution b. Stays in molecular form when dissolved in water c. Dissociates completely when dissolved in water d. Produces very few ions in solution Exercise \(\PageIndex{26}\) Which of the following statements are true about a weak acid? a. Dissociates partially in solution b. All molecules stay in molecular form when dissolved in water c. Dissociates completely when dissolved in water d. Produces lots of ions in solution Dissociation of Weak Acids and Bases Exercise \(\PageIndex{27}\) Which reaction below INCORRECTLY describes the dissociation of the acid: a. \(\ce{HCl} + \ce{H2O} \rightarrow \ce{Cl^-} + \ce{H3O^+}\) b. \(\ce{HNO3} + \ce{H2O} \rightarrow \ce{NO3^-} + \ce{H3O^+}\) c. \(\ce{HC2H3O2} + \ce{H2O} \leftrightarrow \ce{C2H3O2^-} + \ce{H3O^+}\) d. \(\ce{HNO2} + \ce{H2O} \rightarrow \ce{NO2^-} + \ce{H3O^+}\) e. All answers are correct Exercise \(\PageIndex{28}\) Answer the questions that follow using the equation below \[\ce{HF} (g) + \ce{H2O} (l) \rightleftarrows \ce{H3O^+} (aq) + \ce{F^-} (aq) \nonumber\] a. Identify the acid b. Identify the base c. State if the acid is weak or strong d. State if the acid is weak or strong electrolyte Dissociation of Water Exercise \(\PageIndex{29}\) Using the equation below, calculate the molar concentration (M) of acid \(\ce{H3O^+}\) in solution if the concentration of \(\ce{OH^-}\) is \(3.4 \times 10^{-5}\). \[ K_w = 1.0 \times 10^{-14} M^2= [\ce{H3O^+}][\ce{OH^-}] \nonumber\] a. \(2.0 \times 10^{-10}\) b. \(2.4 \times 10^{-10}\) c. \(2.9 \times 10^{-10}\) d. \(3.4 \times 10^{-9}\) e. \(3.4 \times 10^{9}\) Exercise \(\PageIndex{30}\) What is the \([\ce{OH^-}]\) of a solution if \([\ce{H3O^+}]\) is \(4.5 \times 10^{-8}\) M? Exercise \(\PageIndex{31}\) Select the beaker that represents a strong acid solution. a. B b. C c. A d. All of these Exercise \(\PageIndex{32}\) Given that \(K_w = [\ce{H3O^+}][\ce{OH^-}] = 1 \times 10^{-14}\), calculate a. \([\ce{H3O^+}]\), given that \([\ce{OH^-}] = 4.2 \times 10^{‑7}\) b. \([\ce{OH^-}]\), given that \([\ce{H3O^+}] = 8.3 \times 10^{-5}\) The pH Scale Exercise \(\PageIndex{33}\) Which of the following is most acidic? a. coca cola (pH = 3.0) b. apple juice (pH=3.8) c. Bleach (pH = 12.0) d. milk (pH = 6.4) Exercise \(\PageIndex{34}\) A solution at pH 4 is _______ times as _______ as a solution at pH 7. a. 3, acidic b. 100, acidic c. 1000, acidic d. 3, basic e. 100, basic Exercise \(\PageIndex{35}\) Identify each solution as acidic, basic, or neutral. a. \([\ce{H3O^+}] = 1 \times 10^{-8}\) M b. \([\ce{OH^-}] = 1 \times 10^{-7}\) M c. \([\ce{OH^-}] = 4 \times 10^{-11}\) M d. \([\ce{H3O^+}] = 3 \times 10^{-13}\) M Exercise \(\PageIndex{36}\) Matching: Identify each of the following solutions as acidic or basic or neutral a. sweat, pH 5.2 b. saliva, pH 6.8 c. pancreatic juice, pH 8.0 d. urine, pH 5.9 Exercise \(\PageIndex{37}\) Aspirin, which is acetylsalicylic acid, was the first NSAID use to alleviate pain and fever. If a solution of aspirin has an \([\ce{H3O^+}] = 4.7 \times 10^{-2}\) M, what is the pH of the solution? Exercise \(\PageIndex{38}\) A patient experiencing acidosis (pH below normal range) records a blood pH of 7.15. a. What is the hydronium ion concentration (\([\ce{H3O^+}]\)) of the patient’s blood? b. To adjust the patients pH, he should be administered a dose of __________ (acid/base?). Exercise \(\PageIndex{39}\) 39) Little Echo Pond in Adirondacks New York is the most acidic lake in the United States, making it difficult for most plants and fish to survive. What compound below can be used to raise the pH of lakes and restore aquatic life? a. \(\ce{HCl}\) b. \(\ce{CH3CH3}\) c. \(\ce{CaCO3}\) d. \(\ce{CO2}\) e. \(\ce{NaCl}\) Exercise \(\PageIndex{40}\) What is the pH of a solution with an acid concentration of \(9.4 \times 10^{-2}\) M? a. 1.02 b. 1.03 c. 2.97 d. 3.00 e. 13.0 Exercise \(\PageIndex{41}\) What is the \([\ce{H3O^+}]\) of an ammonia cleaning solution with \([\ce{OH^-}] = 4.0 \times 10^{-4}\) M? Is the solution acidic, basic, or neutral? Exercise \(\PageIndex{42}\) The \([\ce{H3O^+}]\) of tomato juice is \(6.3 \times 10^{-5}\) M. What is the \([\ce{OH^-}]\) of the juice? Is the tomato juice acidic, basic, or neutral? Reactions of Acids and Bases Exercise \(\PageIndex{43}\) When a piece of magnesium ribbon is added to an aqueous solution of hydrochloric acid, what gas is produced? a. \(\ce{O2}\) b. \(\ce{H2}\) c. \(\ce{CO2}\) d. \(\ce{H2O}\) e. \(\ce{Cl2}\) Exercise \(\PageIndex{44}\) A CHEM1151K student notices that it takes 20.0 mL of a 1.5 M solution of \(\ce{KOH}\) to completely neutralize 25.0 mL of carbonic acid (\(\ce{H2CO3}\)). What is the molarity of the acid? \[\ce{H2CO3} (aq) + 2\ce{KOH} (aq) \rightarrow \ce{Na2CO3} (aq) + 2\ce{H2O} (l) \nonumber\] a. 0.80 M \(\ce{H2CO3}\) b. 0.40 M \(\ce{H2CO3}\) c. 0.60 M \(\ce{H2CO3}\) d. 1.8 M \(\ce{H2CO3}\) Exercise \(\PageIndex{45}\) What is the molarity of an \(\ce{HCl}\) solution if 30.5 mL of 0.500 M \(\ce{NaOH}\) is required to neutralize 0.0600 L of \(\ce{HCl}\) during a titration? \[\ce{HCl} (aq) + \ce{NaOH} (aq) \rightarrow \ce{NaCl} (aq) + \ce{H2O} (l) \nonumber\] Exercise \(\PageIndex{46}\) Identify each of the following reactions 1: Reaction between acids and metal 2: Reaction between acids and carbonates 3: Reaction between acids and bases 4: Neither a. \(\ce{CaCO3} (s) \rightarrow \ce{CaO} (s) + \ce{CO2} (g)\) b. \(2\ce{H2} (g) + \ce{H2} (g) \rightarrow 2\ce{H2O} (l)\) c. \(2\ce{N2} (g) + 3\ce{H2} (g) \rightarrow 2\ce{NH3} (g)\) d. \(\ce{Ca} (s) + \ce{H2SO4} (aq) \rightarrow \ce{H2} (g) + \ce{CaSO4} (s)\) e. \(3\ce{HCl} (aq) + \ce{Al(OH)3} (aq) \rightarrow 3 \ce{H2O} (l) + \ce{AlCl3} (aq)\) f. \(2\ce{HI} (aq) + \ce{Ba(OH)2} (aq) \rightarrow 2\ce{H2O} (l) + \ce{BaI2} (aq)\) Buffers Exercise \(\PageIndex{47}\) Which of the following statements about buffers is incorrect? a. Buffers contain a weak acid and a salt of its conjugate base b. Buffers maintain physiological pH very close to 7.4 c. Buffers regulate pH by neutralizing added acids or bases d. Buffers have unlimited capacity to neutralize acids and bases e. An example of a buffering system in the human body would be \(\ce{NaHCO3}\) and \(\ce{H2CO3}\) Exercise \(\PageIndex{48}\) \(K_a = [\ce{H3O^+}]\) when the concentration of the acid equals the concentration of its conjugate base in a buffer solution. a. True b. False Exercise \(\PageIndex{49}\) What kind of solution is described by the image below to which drops are added? Choose the most correct answer. a. Strong base b. Water c. Buffer solution d. Precipitate e. Lussacs’ solution Exercise \(\PageIndex{50}\) Identify all the systems below as having components of a buffer solution or not: a. \(\ce{KF}\) and \(\ce{HF}\) b. \(\ce{KBr}\) and \(\ce{HBr}\) c. \(\ce{Na2SO4}\) and \(\ce{H2SO4}\) d. \(\ce{H2CO3}\) and \(\ce{NaHCO3}\) e. \(\ce{HClO2}\) f. \(\ce{HC2H3O2}\) and \(\ce{NaC2H3O2}\) Exercise \(\PageIndex{51}\) The most efficient buffering occurs when the [A\(^-\)]/[HA] ratio is close to _____. a. 1 b. 2 c. 5 d. 10 e. 0.1 Titrations Exercise \(\PageIndex{52}\) The progress of a ________ is represented by plotting the pH of the solution versus the volume of added titrant. A) redox reaction B) titration C) conjugation D) substitution Exercise \(\PageIndex{53}\) Consider the titration of a strong acid HA with a strong base that gives the following titration curve. On the curve, identify the points that correspond to the following questions: a. The stoichiometric (equivalence) point: __________ b. The region with maximum buffering: __________ c. pH = p\(K_a\): __________ d. pH depends only on the amount of excess strong base added: __________ Exercise \(\PageIndex{54}\) If 16.3 mL of a 0.185 M \(\ce{Sr(OH)2}\) solution is used to titrate the \(\ce{HCl}\) in a 25.0-mL (0.0250 L) sample of gastric juice, what is the molarity of the \(\ce{HCl}\) solution? \[2\ce{HCl} (aq) + \ce{Sr(OH)2} (aq) \rightarrow 2\ce{H2O} (l) + \ce{SrCl2} (aq) \nonumber\]