Question

 Get a small piece of a thin strip or ribbon of magnesium & clean its tip with sandpaper.
 Bring the tip near a candle flame.
 It burns with a brilliant white light. When it is completely burnt it leaves behind a powdery ash.
 Now, collect the ash and mix it with a small amount of water.
 Stir the mixture well. Test the mixture with blue and red litmus papers.

What do you observe?

Answer 1

Answer

• When we test the mixture with the blue litmus we see no change. And when we test it on red litmus, it turns blue

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• This reaction is an example of a Chemical Reaction $\sf .$

• Here when we burn the magnesium ribbon Magnesium oxide is Formed

• Magnesium + Oxygen → Magnesium Oxide ❲ Mg + O₂ → MgO ❳

• Then when we add water to Magnesium Oxide it forms Magnesium Hydroxide

• Magnesium + Water → Magnesium Hydroxide ❲ MgO + H₂O → Mg(OH)₂ ❳

• Magnesium hydroxide is a basic substance and so on testing with a red litmus it turns blue but we see no change when it is tested on blue litmus

Answer 2

Blue Lithmus:-

When we Test the mixture with the blue lithmus paper there will be no change in the paper..

Red Lithmus:-

When we Test the mixture with the red lithmus paper there will be a change ( red - blue ) in the paper..

Explanation:-

This is because Magnesium is a basic substance. Basic substance will not have any change in their colour when we Test the mixture with blue lithmus paper..$\:$