Western Cape Education Department
PHYSICAL SCIENCES
Grade 12: June 2025
ACIDS & BASES TUTOR GUIDE
SPRING SCHOOL
1
Grade 12 Spring School Tutoring Programme: Physical Sciences
, ACIDS & BASES – Pre Test
QUESTION 1 (MULTIPLE-CHOICE)
1.1 C
1.2 B
1.3 C
[6]
LONGER EXAM QUESTIONS ANSWERS
QUESTION 2
2.1
2.1.1 𝑝𝐻 = −log [𝐻3 𝑂+ ] (3)
4,2 = −log [𝐻3 𝑂+ ]
[𝐻3 𝑂+ ] = 6,31 𝑥 10−5 mol.dm-3
2.1.2 WEAKER THAN (2)
• H2CO3 has a smaller Ka value than H2SO4, indicating that it ionises in-
completely.
OR
• H2CO3 has a pH of 4,2. Sulphuric acid has a lower pH.
OR
• H2CO3 has a concentration of 0,02 mol.dm-3, but [H3O+] is calculated
at 6,31 x 10-5 mol.dm-3. Therefore carbonic acid ionises incompletely
and is weaker than sulphuric acid that will ionise completely.
(ACCEPT ANY ONE )
SWAKKER AS
• H2CO3 het ‘n laer Ka waarde as H2SO4 wat aandui dat dit onvolledig
ioniseer.
OF
• H2CO3 het ‘n pH van 4,2. Swawelsuur het ‘n laer pH.
OF
• H2CO3 het ‘n konsentrasie van 0,02 mol.dm-3, maar [H3O+] is bereken as
6,31 x 10-5 mol.dm-3. Dus het koolsuur onvolledig ge-ioniseer en is swak-
ker as swawelsuur wat wel volledig ioniseer.
Grade 12 Spring School Tutoring Programme: Physical Sciences 2
PHYSICAL SCIENCES
Grade 12: June 2025
ACIDS & BASES TUTOR GUIDE
SPRING SCHOOL
1
Grade 12 Spring School Tutoring Programme: Physical Sciences
, ACIDS & BASES – Pre Test
QUESTION 1 (MULTIPLE-CHOICE)
1.1 C
1.2 B
1.3 C
[6]
LONGER EXAM QUESTIONS ANSWERS
QUESTION 2
2.1
2.1.1 𝑝𝐻 = −log [𝐻3 𝑂+ ] (3)
4,2 = −log [𝐻3 𝑂+ ]
[𝐻3 𝑂+ ] = 6,31 𝑥 10−5 mol.dm-3
2.1.2 WEAKER THAN (2)
• H2CO3 has a smaller Ka value than H2SO4, indicating that it ionises in-
completely.
OR
• H2CO3 has a pH of 4,2. Sulphuric acid has a lower pH.
OR
• H2CO3 has a concentration of 0,02 mol.dm-3, but [H3O+] is calculated
at 6,31 x 10-5 mol.dm-3. Therefore carbonic acid ionises incompletely
and is weaker than sulphuric acid that will ionise completely.
(ACCEPT ANY ONE )
SWAKKER AS
• H2CO3 het ‘n laer Ka waarde as H2SO4 wat aandui dat dit onvolledig
ioniseer.
OF
• H2CO3 het ‘n pH van 4,2. Swawelsuur het ‘n laer pH.
OF
• H2CO3 het ‘n konsentrasie van 0,02 mol.dm-3, maar [H3O+] is bereken as
6,31 x 10-5 mol.dm-3. Dus het koolsuur onvolledig ge-ioniseer en is swak-
ker as swawelsuur wat wel volledig ioniseer.
Grade 12 Spring School Tutoring Programme: Physical Sciences 2
