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Which element forms an ionic oxide that reacts with strong alkalis? A - AQA - A-Level Chemistry - Question 25 - 2018 - Paper 3
Question 25
Which element forms an ionic oxide that reacts with strong alkalis? A. Aluminium B. Magnesium C. Sodium D. Sulfur
Worked Solution & Example Answer:Which element forms an ionic oxide that reacts with strong alkalis? A - AQA - A-Level Chemistry - Question 25 - 2018 - Paper 3
Step 1
Identify the element that forms an ionic oxide reacting with strong alkalis
Answer
The correct answer is A. Aluminium.
Aluminium oxide (Al₂O₃) acts as an amphoteric oxide, meaning it can react with both acids and alkalis. When aluminium oxide reacts with strong bases, it forms aluminate salts. For example:
ightarrow 4 ext{NaAl(OH)}_4 $$ The other options, although they might form oxides, do not form similar ionic oxides that react with strong alkalis: - **Magnesium** forms magnesium oxide (MgO), which is primarily basic and does not react significantly with alkalis. - **Sodium** forms sodium oxide (Na₂O), which behaves more like a strong base itself in reactions. - **Sulfur** forms oxides like sulfur dioxide (SO₂) and sulfur trioxide (SO₃), which are primarily acidic and do not react with alkalis in the same manner.