DP Chemistry (first assessment 2025)
Question 19M.2.SL.TZ2.5a(i)
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.2.SL.TZ2.5a(i) |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Distinguish | Question number | a(i) | Adapted from | N/A |
a(i).
[Maximum mark: 1]
19M.2.SL.TZ2.5a(i)
(a(i))
Distinguish between a weak and strong acid.
Weak acid:
Strong acid:
[1]
Markscheme
Weak acid: partially dissociated/ionized «in aqueous solution/water»
AND
Strong acid: «assumed to be almost» completely/100 % dissociated/ionized «in aqueous solution/water» [✔]
Examiners report
As expected, many candidates were able to distinguish between strong and weak acids; some candidates referred to “dissolve” rather than dissociate.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.1—Proton transfer reactions » Reactivity 3.1.6—Strong and weak acids and bases differ in the extent of ionization. Recognize that acid–base equilibria lie in the direction of the weaker conjugate. and are strong acids, and group 1 hydroxides are strong bases.