DP Chemistry (last assessment 2024)
Question 17N.2.sl.TZ0.5c
| Date | November 2017 | Marks available | [Maximum mark: 2] | Reference code | 17N.2.sl.TZ0.5c |
| Level | sl | Paper | 2 | Time zone | TZ0 |
| Command term | Evaluate | Question number | c | Adapted from | N/A |
c.
[Maximum mark: 2]
17N.2.sl.TZ0.5c
(c)
A student working in the laboratory classified HNO3, H2SO4, H3PO4 and HClO4 as acids based on their pH. He hypothesized that “all acids contain oxygen and hydrogen”.
Evaluate his hypothesis.
[2]
Markscheme
insufficient data to make generalization
OR
need to consider a «much» larger number of acids
OR
hypothesis will continue to be tested with new acids to see if it can stand the test of time
«hypothesis is false as» other acids/HCl/HBr/HCN/transition metal ion/BF3 do not contain oxygen
OR
other acids/HCl/HBr/HCN/transition metal ion/BF3 falsify hypothesis
correct inductive reasoning «based on limited sample»
«hypothesis not valid as» it contradicts current/accepted theories/Brønsted-Lowry/Lewis theory
[Max 2 Marks]
