Worksheet: The pH Scale

In this worksheet, we will practice defining pH as a logarithmic measure of acid concentration and using it to determine the relative acidity or basicity of a substance.

Q1:

Coffee has a pH of 5. Is it acidic, basic, or neutral?

  • ANeutral
  • BBasic
  • CAcidic

Q2:

Ocean water has a pH of 8. Is it acidic, basic, or neutral?

  • ANeutral
  • BAcidic
  • CBasic

Q3:

Milk of magnesia has a pOH of 3.5. Is it acidic, basic, or neutral?

  • ABasic
  • BAcidic
  • CNeutral

Q4:

Orange juice has a pOH of 9.8. Is it acidic, basic, or neutral?

  • ANeutral
  • BBasic
  • CAcidic

Q5:

In which range of values would the pH of a basic solution be found?

  • A>5
  • B>10
  • C>7
  • D<7
  • E<10

Q6:

Is a solution of pH 6.9 acidic, basic, or neutral?

  • AAcidic
  • BBasic
  • CNeutral

Q7:

In which range of values would the pH of an acidic solution be found?

  • A<7
  • B>5
  • C<5
  • D>7
  • E<10

Q8:

Is a solution of pH 3.2 acidic, basic, or neutral?

  • ABasic
  • BNeutral
  • CAcidic

Q9:

What is the pH of a neutral solution at room temperature?

Q10:

Calcium carbonate will produce a fizz of carbon dioxide when added to lemon juice. Based on this observation, what can be said about the pH of lemon juice?

  • A<10
  • B>5
  • C>7
  • D<7
  • E<5

Q11:

Which of the following pH values would a solution of lemon juice most likely have?

  • A2.5
  • B7.5
  • C0.0
  • D10.0
  • E5.0

Q12:

How can an indicator be used to estimate the pH of a solution?

  • AAn indicator will turn from a solid to a liquid in basic solutions.
  • BAn indicator will make a “squeaky pop” noise in acidic solutions.
  • CAn indicator will change color above or below a specific pH range.
  • DAn indicator can measure the exact concentration of H+ ions in an aqueous solution.
  • EAn indicator will give off a different gas depending on whether a solution is acidic or basic.

Q13:

Fill in the blank: pH is a measurement of the concentration, in an aqueous solution, of .

  • AHO2 molecules
  • BH+ ions
  • Celectrons
  • DH atoms
  • EOH ions

Q14:

A few drops of universal indicator were added to four flasks containing unknown solutions. Which of the following values provide the best estimate for the pH of each solution?

  • AA = 11, B = 1, C = 5, and D = 7
  • BA = 5, B = 7, C = 11, and D = 1
  • CA = 5, B = 1, C = 11, and D = 7
  • DA = 1, B = 11, C = 7, and D = 5
  • EA = 7, B = 11, C = 5, and D = 1

Q15:

In an experiment, a solution of 1 MHSO24 was placed into a beaker. Powdered Ca(OH)2 was added to the beaker at regular intervals and the pH was continually measured. Which of the graphs shows how the pH would change during this experiment?

  • A
  • B
  • C
  • D

Q16:

The table below shows the relationship between pH and the concentration of H+ ions in an aqueous solution. What is the value of 𝑥?

Concentration of H+ ions/mol⋅dm−3 0.1 0.01 𝑥 0.0001 0.00001
pH 1 2 3 4 5
  • A0.0001
  • B0.1
  • C0.001
  • D0.05
  • E0.005

Q17:

Which of the following diagrams represents a correctly labeled pH scale?

  • A
  • B
  • C
  • D

Q18:

Which of the following descriptions explains how litmus paper can be used to test for acids?

  • AAcids turn blue litmus paper red.
  • BAcids keep blue litmus paper blue.
  • CAcids turn red litmus paper blue.
  • DAcids turn red litmus paper purple.
  • EAcids turn blue litmus paper purple.

Q19:

An acidic solution was found to have a pH of 1. Upon the addition of a small volume of a base, the pH changed to 3. By what factor has the concentration of H+ ions changed?

  • AIncreased by a factor of 2
  • BDecreased by a factor of 10
  • CDecreased by a factor of 100
  • DIncreased by a factor of 100
  • EDecreased by a factor of 2

Q20:

Fill in the blanks: Litmus is a mixture of dyes extracted from lichen. It can be used to detect if solutions are acidic or basic. It is in acidic solutions and in basic solutions.

  • Ared, blue
  • Bcolorless, pink
  • Cgreen, blue
  • Dpink, colorless
  • Eblue, red

Q21:

What is the key feature of a chemical that makes it useful as a pH indicator?

  • AColor changes with varying pH
  • BSolubility in water
  • CLow molar mass
  • DCheapness
  • ELow reactivity

Q22:

Which of the following represents the colour of litmus paper in a neutral medium?

  • ABlue
  • BPurple
  • CColourless
  • DRed

Q23:

Which of the following statements about the relationship between [H]+ and [OH] and the value of pH is correct?

  • AIf the concentration of HOH+<, the solution is basic and the value of pH is less than 7.
  • BIf the concentration of HOH+<, the solution is acidic and the value of pH is greater than 7.
  • CIf the concentration of HOH+>, the solution is acidic and the value of pH is less than 7.
  • DIf the concentration of HOH+>, the solution is basic and the value of pH is less than 7.

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