This question is about oxides - AQA - A-Level Chemistry - Question 2 - 2020 - Paper 3
Question 2
This question is about oxides.
Sodium oxide forms a solution with a higher pH than magnesium oxide when equal amounts, in moles, of each oxide are added separately ... show full transcript
Worked Solution & Example Answer:This question is about oxides - AQA - A-Level Chemistry - Question 2 - 2020 - Paper 3
Step 1
State why both oxides form alkaline solutions.
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Answer
Both sodium oxide and magnesium oxide react with water to form hydroxide ions, which increase the solution's pH. For example, sodium oxide reacts with water to produce sodium hydroxide, while magnesium oxide produces magnesium hydroxide. However, sodium hydroxide is more soluble than magnesium hydroxide.
Step 2
Suggest why sodium oxide forms a solution with a higher pH than the solution formed from magnesium oxide.
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Answer
Sodium oxide forms a solution with a higher pH because sodium hydroxide is more soluble than magnesium hydroxide, leading to a greater concentration of hydroxide ions in solution.
Step 3
Give an equation for the reaction between phosphorus(V) oxide and water.
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Answer
The equation for the reaction is:
P4O10+6H2O→4H3PO4
Step 4
Give two equations to show how the vanadium(V) oxide acts as a catalyst in this process.
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