Question

a student burnt the magnesium ribbon in air dissolved the left out ash in water. He further added blue litmus to the solution. He would observe the change in colour of solution form

Answer 1

Answer:

No change would be seen, as the solution of Magnesium hydroxide is basic. Basic solutions turn red litmus blue and no colour change is observed for blue litmus.

Answer 2

The litmus paper stays the same, so there won't be any color variations.

• Here the Magnesium ribbon is first burned in air and then dissolved the remaining ash in water.
• This will result in the formation of a base called Magnesium hydroxide $Mg(OH)_{2}$

       The chemical reactions taking place are,

• Magnesium ribbon burned in the air:

        $2Mg + O_{2}$ → $2MgO$

• In the water, the ash dissolves:

        $MgO + H_{2}O$ → $Mg (OH)_{2}$

• Here, the resulting solution that we get is Magnesium hydroxide, which is a base.
• Chemicals called bases to react with hydrogen ions to neutralize acids.
• Litmus paper is a type of stained paper that can be used to determine whether a given substance is acid or base.
• We know that blue litmus will change to red in acid as well as red litmus will change to blue in base.
• Here, magnesium hydroxide is a base, so red litmus will change to blue, but there will not be any change to blue litmus.
• Hence, the litmus will stay the same.

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