Name:
Date:
SciTec 4
Electrolytes and pH
1. Match each of the terms in the right hand column with the definition given in the right hand
column.
Term
a) Base
b) Acid
c) Neutral substance
Definition
1. Substance with a pH of less than 7
2. Substance with a pH of 7
3. Substance with a pH of more than 7
2. What is pH?
3. For each of the following examples, indicate if the substance is an acid, a base or neutral.
a) A blood sample with a pH of 7.4
b) Salt water with a pH of 7.0
c) Soda drink with a pH of 3.2
d) Window cleaner with a pH of 10.4
e) A KOH solution with a pH of 8.5
f) Lemon juice with a pH of 2.1
4. Among the items in question 3:
a)Which substance is the most acidic? Justify your answer.
b) Which substance is the most basic? Justify your answer.
5. Which of the following describes a neutral salt solution?
A) A solution that does not conduct electricity and that does not change the colour of litmus
paper
B) A solution that conducts electricity and that does not change the colour of litmus paper
C) A solution that conducts electricity and that turns litmus paper red
D) A solution that conducts electricity and that turns litmus paper blue
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Name:
Date:
SciTec 4
6. Classify the following substances by type of electrolyte (acid, base or salt).
KOH
Ba(NO3)2
KF
H2SO3
HNO3
Na2CO3
Mg(OH)2
NH4OH
Fe(OH)3
HCl ________________
MgCl2
________________
Ca(OH)2 ______________
7. To check the electrical conductivity of certain substances, a student used a conductivity
apparatus equipped with a light bulb. Her observations are listed in the following table.
Which one of the following groups of substances contains only electrolytes?
A) CH3OH and CCl4
B) HCl , MgCl2 and CCl4
C) CH3OH NaOH and CH3COOH
D) HCl, MgCl2, NaOH and CH3COOH
1.
2.
3.
4.
8. Which of the following are acids?
NaCl
5.
HI
HCl
6.
HCH3CO2
LiF
7.
KOH
NH4OH
8.
CaCl2
A) 1, 5 and 8
B) 5, 6 and 8
C) 2, 5 and 6
D) 3, 4 and 7
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1.
2.
3.
4.
SciTec 4
9. Which of the following are bases?
NaOH
5.
BeO
HCl
6.
HI
LiF
7.
KOH
NH4OH
8.
CaCl2
A) 1, 4 and 7
B) 3, 5 and 6
C) 2, 3 and 8
D) 1, 3 and 7
10. A student must classify six aqueous solutions.
The student knows that all except one of the solutions must be an ACID, a BASE, or a NEUTRAL
SALT. The student writes a procedure and carries out certain tests.
The table shows the results that were obtained.
Solution
Litmus paper
Electrical conductivity
1
No effect
Good
2
Turned blue
Good
3
Turned red
Good
4
No effect
None
5
Turned blue
Weak
6
Turned blue
Good
Based on these results, which conclusion is the most appropriate?
A) Solutions 2, 5 and 6 are bases, solution 3 is an acid and solutions 1 and 4 are salts
B) Solutions 2, 5 and 6 are acids, solution 3 is a base and solutions 1 and 4 are distilled water
C) Solutions 2, 5 and 6 are bases, solution 3 is an acid, solution 1 is a salt and solution 4 cannot
be classified
D) Solutions 2, 5 and 6 are acids, solution 3 is a base, and solutions 1 and 4 are salts
11. Which of the following is a non-electrolyte?
A) Mg(OH)2
B) H2SO4
C) P2S3
D) CaCl2
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SciTec 4
12. In the lab, you are given two acidic solutions. One has a pH value of 5, and the
other has a pH value of 6.8. Name the best indicator that would allow you to distinguish between the
two solutions?
1) Methyl orange
pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14
red
Orange
yellow
2) Bromothymol blue
pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Yellow
Green
blue
3) Phenolphthalein
pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Colourless
pink
dark pink
4) m-Cresol purple
pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Yellow
brown violet
13. The following table gives the colours of two acid-base indicators when they are added to
solutions with different pH values.
pH Scale
Indicator 1
1
Red
3
5
7
Orange
Yellow
9
11
13
Yellow
Green
Blue
Indicator 2
The pH of solution A is 2 and the pH of solution B is 13. What was the colour of solution A and the colour
of solution B with each indicator (indicator1/indicator2)?
A) Solution A is red/yellow and solution B is yellow/blue.
B) Solution A is yellow/yellow and solution B is yellow/blue.
C) Solution A is orange/yellow and solution B is yellow/green.
D) Solution A is red/yellow and solution B is yellow/blue.
14. Which of these aqueous solutions contains a neutral salt?
A) Solution 1
B) Solution 2
C) Solution 3
D) Solution 4
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