Worksheet: Conjugate Acid–Base Pairs

In this worksheet, we will practice identifying conjugate acids and bases in chemical equations and predicting their relative acid or base strengths.

Q1:

In the equation

N H 3 is the conjugate acid. What is the missing term?

  • A N H 2 4
  • B N H 3
  • C N H 4 +
  • D N H 2

Q2:

Give the formula and state symbol of the missing compound in the equation:

  • A H S ( ) 2 g
  • B S O ( ) 2 g
  • C H S O ( ) 2 3 a q
  • D S O ( ) 3 2 a q
  • E H S O ( ) 2 4 a q

Q3:

In the equation

H P O 2 4 is the conjugate base. What is the missing term?

  • A P O 4 3
  • B H P O 2 4
  • C H P O 2 3 +
  • D H P O 3 4
  • E H P O 4 2

Q4:

What is the conjugate acid of O H ?

  • A H O 2 2
  • B H O 3 +
  • C O 2
  • D H O 2

Q5:

What is the conjugate acid of H O 2 ?

  • A H O 2 2
  • B O H
  • C O 2
  • D H O 3 +

Q6:

What is the conjugate acid of H S ?

  • A S O 2
  • B S 2
  • C H S 2

Q7:

In the equation N H 3 is the conjugate base. What is the missing term?

  • A N H 2 4
  • B N H 3
  • C N H 2
  • D N H 4 +

Q8:

H S O 2 4 and C l ions react according to the equation:

Which species is the Brønsted-Lowry acid in this reaction?

  • A H C l
  • B C l
  • C H S O 4
  • D H S O 2 4

Which species is the conjugate base of the Brønsted-Lowry acid in this reaction?

  • A H C l
  • B C l
  • C H S O 2 4
  • D H S O 4

Which species is the Brønsted-Lowry base in this reaction?

  • A C l
  • B H S O 2 4
  • C H C l
  • D H S O 4

Which species is the conjugate acid of the Brønsted-Lowry base in this reaction?

  • A H C l
  • B H S O 4
  • C H S O 2 4
  • D C l

Q9:

In the reaction

which species is a Brønsted-Lowry acid?

  • A S O 4 2
  • B O H
  • C H O 2
  • D H S O 4

which species is the conjugate base of a Brønsted-Lowry acid?

  • A H O 2
  • B O H
  • C H S O 4
  • D S O 4 2

which species is a Brønsted-Lowry base?

  • A O H
  • B H S O 4
  • C S O 4 2
  • D H O 2

which species is the conjugate acid of a Brønsted-Lowry base?

  • A H O 2
  • B S O 4 2
  • C H S O 4
  • D O H

Q10:

Two aqueous complex ions react according to the equation:

Which species is the Brønsted-Lowry acid in this reaction?

  • A [ C u ( H O ) ] 2 4 2 +
  • B [ C u ( H O ) ( O H ) ] 2 3 +
  • C [ A l ( H O ) ( O H ) ] 2 5 2 +
  • D [ A l ( H O ) ] 2 6 3 +

Which species is the conjugate base of the Brønsted-Lowry acid in this reaction?

  • A [ C u ( H O ) ] 2 4 2 +
  • B [ A l ( H O ) ] 2 6 3 +
  • C [ C u ( H O ) ( O H ) ] 2 3 +
  • D [ A l ( H O ) ( O H ) ] 2 5 2 +

Which species is the Brønsted-Lowry base in this reaction?

  • A [ C u ( H O ) ( O H ) ] 2 3 +
  • B [ A l ( H O ) ] 2 6 3 +
  • C [ C u ( H O ) ] 2 4 2 +
  • D [ A l ( H O ) ( O H ) ] 2 5 2 +

Which species is the conjugate acid of the Brønsted-Lowry base in this reaction?

  • A [ C u ( H O ) ] 2 4 2 +
  • B [ A l ( H O ) ( O H ) ] 2 5 2 +
  • C [ C u ( H O ) ( O H ) ] 2 3 +
  • D [ A l ( H O ) ] 2 6 3 +

Q11:

For the reaction of mercury(II) chloride and ammonia, which product is a conjugate Lewis base?

  • A H g C l 2
  • B N H 3
  • C H g ( N H ) 3 2
  • D C l

Q12:

Gastric juice, the digestive fluid produced in the stomach, contains hydrochloric acid, H C l . Milk of magnesia, a suspension of solid M g ( O H ) 2 in an aqueous medium, is sometimes used to neutralize excess stomach acid:

What value of 𝑥 produces a balanced chemical equation?

What is the conjugate acid of M g ( O H ) 2 ?

  • A H O 2
  • B H C l
  • C M g 2 +
  • D C l
  • E M g C l 2

Q13:

Why does the complete reaction of a weak acid with a strong base produce a basic solution?

  • AWater competes with the weak acid to react with the base, raising the concentration of hydroxide ions.
  • BAn excess of strong base must be used for the reaction to reach completion.
  • CThe reaction produces a weak conjugate base and no conjugate acid.
  • DThe reaction produces a strong conjugate base and a weak conjugate acid.
  • EThe reaction produces ions that interact strongly with hydroxide ions in solution, stabilizing their negative charge.

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.