Hydrochloric acid is often used to clean metals by reacting with the surface coating which develops on some metals when exposed to the atmosphere.
Which row correctly describes the surface coating on these metals?
| name | acidic or basic | reacts with | |
| A | oxide | basic | acid |
| B | oxide | acidic | basic |
| C | alloy | acidic | basic |
| D | alloy | basic | acid |
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Which of the following elements forms an oxide that can be used to neutralise an alkaline solution?
Nitrogen
Magnesium
Iron
Helium
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When heated, magnesium reacts with oxygen in the air to form magnesium oxide, a white powder.
A student investigates the change in mass that occurs during this reaction. The student is given a balance and the three sets of apparatus shown.
Which sets of apparatus are suitable for this investigation?
1, 2 and 3
1 and 3 only
2 and 3 only
2 only
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