Acids and Bases Practice Problems

Complete the following equations by writing the missing products in each of the acid-base reactions given below.
a. CH₃COOH + NH₃ ⇌
b.+ ^-OCH₃ ⇌

Write possible products for the acid-base reaction below:

C₆H₅COOH + CH₃NH₂ ⇌

Estimate the pH of each solution given below based on hydronium or hydroxide concentration without using a calculator.

(i) [HO⁻] = 2.4 × 10⁻⁹ M
(ii) [H₃O⁺] = 3.5 × 10⁻² M
(iii) [H₃O⁺] = 5.7 × 10⁻⁴ M

Determine the exact pH by using a calculator.

Draw the products of the acid-base reaction shown below and identify the acid, base, conjugate acid, and conjugate base.

Consider the following reaction of the amide ion and determine which definition of base is being demonstrated here.

Predict the product in the reaction of the following molecule with one equivalent of a strong base.

Determine the identity of products that are formed in the reaction between each of the species given below with CH₃O⁻.
(i) CH₃CH₂OH
(ii) CH₃NH₃⁺

Propose the most probable arrow-pushing mechanism for the Lewis acid-base reaction of bromine and ferric bromide. Indicate the Lewis acid and the Lewis base.

For each reaction given below, determine the products. Also indicate where the pair of electrons starts and where it ends up using curved arrows.

Based on the labelled species, identify the rest as acid, base, conjugate acid, and conjugate base in the reaction given below.

Determine the conjugate acid formed from the protonation of the atom indicated in the given base.

Two solutions were prepared by: (i) dissolving 3.00 g of HCl in 200 mL of aqueous solution, and (ii) dissolving 3.00 g of NaOH in 100 mL of aqueous solution. Determine the pH of each solution.

H₂SO₄ has been known to be a very strong acid. What is its conjugate base? Also, determine if the conjugate base is weak/strong and reactive/unreactive.

Provide the conjugate acid of the base and conjugate base of the acid given on the right side of the following reaction.

HC≡C⁻  +  HCl  ⇌  HC≡CH  +  Cl⁻

Label the acid, base, conjugate acid, and conjugate base in the given reaction using the convention that the acid and base are on the left side of the equation.

How can molecules A, B, and C be separated?

Consider the following acid-base reaction:

NH₃ + BF₃ ⇌ H₃N⁺—BF₃⁻

1. For all the reactants and products, draw Lewis structures.
2. Identify the nucleophile (base) and electrophile (acid) in the reaction.
3. Draw curved arrows to show the flow of electrons.
4. Determine if the reaction can be termed a Brønsted-Lowry acid-base reaction.

Draw the products of the reaction given below and identify the acid, base, conjugate acid, and conjugate base.

For the reaction between HCOO⁻ and HCl given below, identify the following:

(i) The acid on the left side of the chemical equation.
(ii) The base on the left side of the chemical equation.

HCOO⁻(aq) + HCl(aq) → HCOOH(aq) + Cl⁻(aq)

Write the conjugate base of the acid given below formed by losing the indicated proton.

Which of the reactants is the Lewis acid and which one is the Lewis base in the reaction given below?

Draw the arrow-pushing mechanism to show the flow of electrons in the following base half-reaction of isopropyl amine. 

Consider the following reaction:

Identify the Lewis acid (electrophile) and Lewis base (nucleophile) in these reactions and draw curved arrows to indicate the flow of electrons.

Give a plausible mechanism involving arrow-pushing for the Lewis acid-Lewis base reactions provided below.

The following compounds are known as antacids because they can react with stomach acid and neutralize it. Write the chemical equations that illustrate how each of the compounds given below can remove excess acid.

(i) Al(OH)₃
(ii) Mg(HCO₃)₂ and Ca(HCO₃)₂
(iii) MgCO₃

Draw the anion formed when the following molecule is treated with one equivalent of a strong base.

Determine the acid that produced the given conjugate base. The most basic atom in the conjugate base is highlighted.

Draw curved arrows to demonstrate the movement of electrons in the given acid-base reaction. 

Show the most plausible arrow-pushing mechanism for the acid-base reaction of boron trichloride and butan-1-ol. Identify the role of the hydroxyl group of butan-1-ol from the following: Lewis acid, Lewis base, non-Lewis acid, or non-Lewis base. 

Write the conjugate acid produced from the protonation of the indicated atom in the base below.

Write the conjugate bases for the below-given species.

a. HI

b. H₂SO₄

c. CH₃OH

d. HNO₂

Identify the remaining molecules as acid, base, conjugate acid, or conjugate base using the one already labeled.

Write the base which formed the given conjugate acid. The most acidic atom in the conjugate acid is indicated.

Draw the Lewis acid-base adduct produced by each of the reactions listed below.

Show the product formed from the intramolecular Lewis acid-base reaction of 6-hydroxyoctan-2-ylium.

Write the conjugate base that is created by losing the indicated proton in the acid below.

Determine the identity of the major product of the reaction shown below.

Complete the reaction given below and identify the acid, base, conjugate acid, and conjugate base.

Like radicals, anions, and cations, carbenes are also reactive intermediates. Looking at the structure of carbene shown below, explain why carbenes are also Lewis bases besides being Lewis acids.

In the acid-base equilibrium shown below, determine the acid and corresponding conjugate acid.

Which of the structures given below are not acids?

CH₃CH₂CH₂COOH, CO₃²⁻, HNO₃, C₆H₅COOH, CBr₄

Show the arrow-pushing mechanism indicating the flow of electrons in the following acid half-reaction. 

Like radicals, anions, and cations, carbenes are also reactive intermediates. Considering the structure of carbene shown below, explain why carbenes are Lewis acids.

Determine the products that are formed in a reaction between each of the species given below with   CH₃O⁻.
(i) CH₃⁺
(ii) AlBr₃

Write the conjugate acids for the below-given species.

a. CH₃O⁻

b. CH₃OH

c. CH₃CH₂COO⁻

Write the products formed as a result of the acid-base reaction between the following compounds.
a. 2⁻OH + HOOC—COOH ⇌

b. HCOO⁻  + HCl ⇌

On the basis of the species that is identified, label the rest as acid, base, conjugate acid, and conjugate base in the reaction given below.

Draw the structures of conjugate bases for the following acids.

Draw any resonance forms, if applicable, and arrange the conjugate bases from the least stable to the most stable.

Draw the product/s of the Lewis acid-base reaction of bromine cation and 2-methylpropan-2-amine. 

Methylamine (CH₃NH₂) is an organic nitrogenous compound. Write chemical equations showing how methylamine acts as an acid and a base. When in an aqueous solution, does methylamine act as an acid or a base? Also, write equations for how water acts both as an acid and a base.

Consider the below-given reaction and answer each of the following questions.

(a) Which reactant is the acid, and which one is the base?

(b) Which is the most acidic proton in the acid?

(c) Which is the most electron-rich atom in the base?

Provide the conjugate acid of the base and conjugate base of the acid given on the left side of the following reaction.

HC≡C⁻  +  HCl  ⇌  HC≡CH  +  Cl⁻

Draw the anion formed when the following molecule is treated with one equivalent of a strong base.

Write possible products for the acid-base reaction below:

C₆H₅NH₃⁺ + CH₃CH₂O⁻ ⇌

Draw the anion obtained in the reaction of the following molecule with one equivalent of a strong base.

Consider the reaction given below to answer the following questions:

(a) Which reactant is the acid and which one is the base?

(b) Which is the most acidic proton in the acid?

(c) Which is the most electron-rich atom in the base?

Use curved arrows to show the movement of electrons in the following acid-base reaction. 

Draw the arrow-pushing mechanism for the acid half-reaction of the protonated form of dipropylketone. 

What anion is formed when the following molecule is treated with one equivalent of a strong base?

Provide an arrow-pushing mechanism for the following reaction and predict the products.

Consider the following acid-base reaction:

H₂C=CH₂ + HBr ⇌ H₃C—CH₂⁺ + Br⁻

1. For all the reactants and products, draw Lewis structures.
2. Identify the nucleophile (base) and electrophile (acid) in the reaction.
3. Draw curved arrows to show the flow of electrons.
4. Determine if the reaction can be termed a Brønsted-Lowry acid-base reaction.

Draw the products expected in the reaction of the following molecule with one equivalent of a strong base.

Provide the products of the following reaction and propose an arrow-pushing mechanism for their formation.

Sketch the arrow-pushing mechanism for the given reactant of a base-catalyzed intramolecular reaction.

Write the acid that yields the given conjugate base. The most basic atom in the conjugate base is highlighted.

Draw the products expected in the following acid-base reaction and identify the acid, base, conjugate acid, and conjugate base.

Write possible products for the acid-base reaction below:

(C₂H₅)₂NH₂⁺ + OH⁻ ⇌

A student prepares a buffer solution by dissolving CH₃CH₂COOH and CH₃CH₂COO⁻K⁺ in pure water. Write the chemical equations that illustrate how the components of the buffer are able to prevent a drastic change in the pH of the solution when the student adds:
(i) a small amount of H⁺ into the solution.
(ii) a small amount of HO⁻ into the solution.

Indicate the acid, base, conjugate acid, and conjugate base in the given reaction using the convention that the acid and base are on the left side of the chemical equation.

An unknown compound that has been identified as a strong acid will have a conjugate base that is both reactive and unstable. True or false?

Amide ion is a very strong base. Consider the following reaction of the amide ion and determine which definition of base is being demonstrated.

Draw the conjugate acids for the below-given species.

a. Br⁻

b. NH₂⁻

c. HCO₃⁻

d. HS⁻

Write possible products for the acid-base reaction below:

CH₃CH₂NH₂ + HCOOH ⇌

Predict the products in the following reaction and propose an arrow-pushing mechanism for their formation.

Consider the following acid-base reaction to answer these questions.

(a) Which reactant is the acid and which one is the base?

(b) Which is the most acidic proton in the acid?

(c) Which is the most electron-rich atom in the base?

Determine the conjugate base of the acid below formed by losing the indicated proton.

Mark the bonds that are broken and formed in reaction. Label the bonds that were formed or broken as a sigma (σ) bond or a pi (π) bond.

Provide a brief explanation as to why BH₃ is a Lewis acid at B but the molecule NH₃ is not a Lewis acid at N.

Explain briefly what makes the ions like H₂N^- a Lewis base.

Potassium hydroxide (KOH) splits into a potassium cation (K⁺) and hydroxide (HO^-) a strong base. Identify which definition/s of base is being illustrated in the reaction below.

Identify which between Cl^- and Br^- is the harder Lewis base. Justify your answer.

Identify which between H⁺ and K⁺ is the harder Lewis acid. Justify your answer.

Phenylmethylene is an example of a carbene with the molecular formula C₇H₆. It can act as both a Lewis acid and a Lewis base. Why?

Identify the Lewis base and acid in the reaction. Provide an arrow-pushing mechanism that accounts for the formation of the following Lewis acid–Lewis base complex.

Provide a brief explanation as to why SiH₃^- is a Lewis base at Si but the molecule AlH₄^- is not a Lewis base at Al.

Perchloric acid is a strong acid. Explain how HClO₄ satisfies the Arrhenius, Brønsted–Lowry, and Lewis acid definitions.

Which between Ca²⁺ and Li⁺ is the harder Lewis acid? Justify your answer.

Is a base that has a conjugate acid with a low pK_a value considered to be stable or unstable? Provide a brief explanation for your answer.

If the acid and base are on the reactant (left) side of the chemical equation, which of the following labels the base, acid, conjugate base, and conjugate acid in the reaction shown below?

Explain the following:

In an acid-base reaction, when an atom loses a proton, its formal charge is decreased by one.

For the reaction shown below,

(i) Label the acid and base.

(ii) Determine the most electron-rich atom in the base.

(iii) Determine the most acidic hydrogen in the acid.

(iv) Draw the arrow-pushing mechanism to predict the products.

Suggest an acid-base extraction scheme for the separation of a mixture of the following molecules in diethyl ether. Note that N-ethylaniline is an amine and is basic, while 2,3-dimethylnaphthalene is an aromatic compound.

Phosphoglucoisomerase catalyzes the isomerization of D-glucose-6-phosphate to D-fructose-6-phosphate. Amino acid residues in the enzyme's active site carry out the acid-base catalysis. Suggest a mechanism for the isomerization reaction. Simplify to show only the reacting region.

An amino acid such as glycine has a carboxylic acid group and a protonated amine group.

i. Is there a pH at which glycine is uncharged?

ii. At what pH does glycine have no net charge?

Draw the form of phenol, C₆H₅OH (pK_a = 9.95) that predominates at the pH of (i) 4, (ii) 7, (iii) 11, and (iv) 13.

Determine the products formed when i. (CH₃)₂CHNH₃⁺ or ii. AlCl₃ reacts with HO^-.

Illustrate the conjugate base if the given compound acts as an acid. Show any resonance forms if applicable.

Rank the conjugate bases of the following molecules from most stable to least stable.

Draw the conjugate acids and estimate the pK_a of the structures shown below.

Ethanol (CH₃CH₂OH) can serve as both an acid and a base. Write an equation for the reaction of ethanol with HNO₃ and NH₂^-.

Hexan-1-ol is oxidized to hexanal using PCC. However, some over-oxidation occurred, and some hexan-1-ol was oxidized to hexanoic acid.

(i) Provide a step-by-step process of purifying hexanal using acid-base extraction.

(ii) Which substance in the reaction mixture cannot be separated from hexanal using acid-base extraction? How can the two be separated?

The boiling points of oct-1-yne and oct-1-ene are 126.3 °C and 121.3 °C, respectively, making it implausible to completely separate them using distillation. Explain how the concept of acidity might be used to remove oct-1-yne from a sample of oct-1-ene completely.

The following compounds can react as bases:

(i) NH₃, (ii) CH₃CH₂SH, (iii) KOH, (iv) CH₃CH₂CONH₂

Draw the conjugate acids of the given bases. If resonance is possible for the conjugate acid, show it.

Determine the plausible products of the acid-base reactions given below.

(i) CH₃CH₂COOH + CH₃O^- ⇌

(ii) ⁺NH₃CH₂CH₂CH₂COOH + 2 ^-OH ⇌