Differences between the properties of metals and non-metals
4 marks · NormalState the general rule for the acid–base character of oxides of metals and of non-metals.
Give a specific example of (i) a basic oxide and (ii) an acidic oxide. Write a balanced chemical equation for the reaction of the acidic oxide with sodium hydroxide.
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(a) Metal oxides are generally basic; non-metal oxides are generally acidic.
(b) Basic oxide: magnesium oxide (MgO). Acidic oxide: carbon dioxide (CO2). Balanced equation: CO2 + 2NaOH → Na2CO3 + H2O.
Also accept: a) Metal oxides are usually basic, non-metal oxides are usually acidic. b) Basic oxide: MgO or CuO; Acidic oxide: SO2 or CO2; SO2 + 2NaOH → Na2SO3 + H2O or CO2 + 2NaOH → Na2CO3 + H2O.
Common mistakes: Mixing up basic and acidic oxide examples
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Marking points
B1 (a) · 1 mark · States metals form basic oxides.
B2 (a) · 1 mark · States non-metals form acidic oxides.
B3 (b) · 1 mark · Gives correct specific example for each (basic and acidic).
B4 (b) · 1 mark · Correctly writes balanced chemical equation for acidic oxide reaction with NaOH.
Worked solution
a) Metal oxides tend to be basic; non-metal oxides tend to be acidic. b) Basic oxide: magnesium oxide (MgO). Acidic oxide: carbon dioxide (CO2). The balanced reaction: