Lesson test: Acids and bases

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Acids and bases

1.[2p]
What is the pH of $0.025$ mol dm⁻³ nitric acid at $25$ °C?

CorrectNot quite: 1.60

2.[3p]
Acetic acid has $K_{a} = 1.75 \times 10^{- 5}$ . What is the pH of a $0.100$ mol dm⁻³ solution?

CorrectNot quite: 2.88

3.[3p]
Why is neutral water at $60$ °C at pH $6.51$ rather than $7.00$ ?

$K_{w}$ rises with temperature, so both ion concentrations are larger while still equal

Correct

The water has absorbed carbon dioxide

The answer is: $K_{w}$ rises with temperature, so both ion concentrations are larger while still equal

The pH scale is defined only at 25 degrees Celsius

The answer is: $K_{w}$ rises with temperature, so both ion concentrations are larger while still equal

Hot water contains more hydronium than hydroxide

The answer is: $K_{w}$ rises with temperature, so both ion concentrations are larger while still equal

4.[2p]
Ammonia has $K_{b} = 1.8 \times 10^{- 5}$ . What is $K_{a}$ for the ammonium ion, taking $K_{w} = 1.0 \times 10^{- 14}$ ?

CorrectNot quite: 5.6e-10

5.[2p]
The approximation $[] = \sqrt{K_{a} C}$ is safe for $0.0010$ mol dm⁻³ acetic acid.

True

The answer is: False

False

Correct

6.[2p]
Hydrochloric, nitric and perchloric acids all appear equally strong in water. What is this called?

The levelling effect

Correct

The common ion effect

The answer is: The levelling effect

The inductive effect

The answer is: The levelling effect

The salt effect

The answer is: The levelling effect

7.[2p]
Chloroacetic acid has $K_{a} = 1.36 \times 10^{- 3}$ . What is its $p K_{a}$ ?

CorrectNot quite: 2.87

8.[3p]
Match each aqueous solution to what it is.

Sodium acetate
Ammonium chloride
Sodium chloride
Sodium hydrogencarbonate

acidic
neutral
alkaline
alkaline

Show the answer

Sodium acetate: alkaline Ammonium chloride: acidic Sodium chloride: neutral Sodium hydrogencarbonate: alkaline

9.[3p]
Which explain why one acid is stronger than another?

Select all that apply

A weaker bond to hydrogen, as down the halogen group

Correct

More oxygen atoms pulling charge off the anion, as in the chlorine oxoacids

Correct

Electronegative substituents nearby, as in chloroacetic acid

Correct

A larger concentration of the acid in the bottle

The answer is: A weaker bond to hydrogen, as down the halogen group, More oxygen atoms pulling charge off the anion, as in the chlorine oxoacids, Electronegative substituents nearby, as in chloroacetic acid

1.[2p] What is the pH of 0.025 mol dm⁻³ nitric acid at 25 °C?

2.[3p] Acetic acid has Ka=1.75×10−5. What is the pH of a 0.100 mol dm⁻³ solution?

3.[3p] Why is neutral water at 60 °C at pH 6.51 rather than 7.00?

4.[2p] Ammonia has Kb=1.8×10−5. What is Ka for the ammonium ion, taking Kw=1.0×10−14?

5.[2p] The approximation []=KaC is safe for 0.0010 mol dm⁻³ acetic acid.

6.[2p] Hydrochloric, nitric and perchloric acids all appear equally strong in water. What is this called?

7.[2p] Chloroacetic acid has Ka=1.36×10−3. What is its pKa?

8.[3p] Match each aqueous solution to what it is.

9.[3p] Which explain why one acid is stronger than another?

1.[2p]
What is the pH of $0.025$ mol dm⁻³ nitric acid at $25$ °C?

2.[3p]
Acetic acid has $K_{a} = 1.75 \times 10^{- 5}$ . What is the pH of a $0.100$ mol dm⁻³ solution?

3.[3p]
Why is neutral water at $60$ °C at pH $6.51$ rather than $7.00$ ?

4.[2p]
Ammonia has $K_{b} = 1.8 \times 10^{- 5}$ . What is $K_{a}$ for the ammonium ion, taking $K_{w} = 1.0 \times 10^{- 14}$ ?

5.[2p]
The approximation $[] = \sqrt{K_{a} C}$ is safe for $0.0010$ mol dm⁻³ acetic acid.

6.[2p]
Hydrochloric, nitric and perchloric acids all appear equally strong in water. What is this called?

7.[2p]
Chloroacetic acid has $K_{a} = 1.36 \times 10^{- 3}$ . What is its $p K_{a}$ ?

8.[3p]
Match each aqueous solution to what it is.

9.[3p]
Which explain why one acid is stronger than another?