Question 19M.3.hl.TZ2.1b(ii)
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.hl.TZ2.1b(ii) |
| Level | hl | Paper | 3 | Time zone | TZ2 |
| Command term | Examine | Question number | b(ii) | Adapted from | N/A |
This question is about a mug made of a lead alloy.
The rate of lead dissolving in common beverages with various pH values was analysed.
Examine, giving a reason, whether the rate of lead dissolving increases with acidity at 18 °C.
[1]
no AND experiment 7/beer has lowest rate and intermediate acidity/pH
OR
no AND experiment 6/orange juice has fastest rate but lower acidity/higher pH than lemonade
OR
no AND experiment 6/orange juice has highest rate and intermediate acidity/pH [✔]
Note: Accept no AND any comparison, with experimental support, that concludes no pattern/increase with acidity
eg: “rate of Pb/lead dissolving generally decreases with acidity as tap water has highest rate (after orange juice) while lemonade (lower pH) has lower rate”.
The candidates who examined the data and quoted it in their answer generally scored the mark but several candidates did not refer to the data table.
