DP Chemistry (last assessment 2024)
Question 19M.2.sl.TZ2.5b(iii)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.sl.TZ2.5b(iii) |
| Level | sl | Paper | 2 | Time zone | TZ2 |
| Command term | Identify | Question number | b(iii) | Adapted from | N/A |
b(iii).
[Maximum mark: 2]
19M.2.sl.TZ2.5b(iii)
Carbonated water is produced when carbon dioxide is dissolved in water under pressure.
The following equilibria are established.
Soda water has sodium hydrogencarbonate, NaHCO3, dissolved in the carbonated water.
(b(iii))
Identify the type of bonding in sodium hydrogencarbonate.
Between sodium and hydrogencarbonate:
Between hydrogen and oxygen in hydrogencarbonate:
[2]
Markscheme
Between sodium and hydrogencarbonate:
ionic [✔]
Between hydrogen and oxygen in hydrogencarbonate:
«polar» covalent [✔]
Examiners report
Many candidates identified the bonding between sodium and hydrogencarbonate as ionic. A much smaller proportion of candidates identified the bonding between hydrogen and oxygen in hydrogencarbonate as covalent. The most common mistake was “hydrogen bonding”.
