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. Sodium oxide reacts more readily with water compared to magnesium oxide, producing hydroxide ions, thus resulting in alkaline solutions.
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 is more soluble in water than magnesium oxide. Consequently, it produces a greater concentration of hydroxide ions, leading to a higher pH for the sodium oxide solution.
Step 3
Give an equation for the reaction between phosphorous(V) oxide and water.
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Answer
The equation for the reaction is:
P2O5+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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