2021 P1 Q9 - Solubility and Acid Base Reaction of Silicon Dioxide
Let's take a look at 2021 A Levels H2 Chemistry Paper 1 Question 9.
We are required to determine the observations for the 3 experiments involving silicon dioxide.
Recall that silicon dioxide is a giant molecule with strong and extensive covalent bonds.
SiO2 is also a non-metal oxide hence it is acidic in nature.
1. Shake with an excess of water
Silicon dioxide is not soluble in water since the interaction between SiO2 and water molecules is insufficient to overcome the strong and extensive covalent bonds in the giant molecule.
We will expect SiO2 solid to remain for experiment 1.
2. Shake with an excess of dilute NaOH(aq)
Silicon dioxide is acidic in nature but will only react with hot concentrated NaOH due to its strong and extensive covalent bonds.
Therefore SiO2 will not react with dilute NaOH.
We will expect SiO2 solid to remain for experiment 2.
3. Shake with an excess of dilute HCl(aq)
Silicon dioxide is acidic and will not react with HCl which is also an acid.
We will expect SiO2 solid to remain for experiment 3 as well.
Hence a solid is expected to remain for all three experiments, and option D is our answer to this question.
Topic: Periodicity, Inorganic Chemistry, A Level Chemistry, Singapore
Back to list of questions for 2021 A Level H2 Chemistry Paper 1.
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