Cleaning magnesium ribbon before burning removes which obstacle?
Answer and explanation
Correct answer: Surface oxide layer
Magnesium reacts with oxygen in air to form a thin, stable layer of magnesium oxide on its surface. This coating prevents fresh magnesium from contacting oxygen easily and can delay or weaken ignition. Rubbing the ribbon with sandpaper removes the oxide layer, exposing clean magnesium so the combustion reaction starts clearly. Oxygen is still needed and remains present; liquid magnesium and white powder are not the obstacle being removed.
Frequently asked questions
What is the correct answer to this question?
Surface oxide layer
Why is this the correct answer?
Magnesium reacts with oxygen in air to form a thin, stable layer of magnesium oxide on its surface. This coating prevents fresh magnesium from contacting oxygen easily and can delay or weaken ignition. Rubbing the ribbon with sandpaper removes the oxide layer, exposing clean magnesium so the combustion reaction starts clearly. Oxygen is still needed and remains present; liquid magnesium and white powder are not the obstacle being removed.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
