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why the blue litmus paper turn purple when kept in neutral substance ?why not remain in same colour ?

Dear student!

Actually, the litmus paper is blue, when its pH is 8 i.e. it is slightly alkaline, but when it is dipped in a neutral solution with pH 7 , the color faints and that becomes purple which is the actual color of neutral litmus paper. 

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Blue litmus paper stays blue in a neutral solution. It turns red only when in an acidic solution. Similarly, red litmus paper would stay red in a neutral solution and turn blue in an alkaline solution.

Added:acidic: pH below 5.5 it turns (stays) redalkaline: pH above 8.0 it turns (stays) blueneutral, in between 5.5 and 8.0: its color is purple,between 'red and blue' or 'blue and red'

A much better indicator paper is universal indicator paper. It is yellow and can tell you the exact pH of the solution it is dipped in, going yellow to red in acidic conditions, blue to purple in alkaline conditions and green in neutral conditions. The exact colour depends on the pH.

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Blue litmus paper stays blue in a neutral solution. It turns red only when in an acidic solution. Similarly, red litmus paper would stay red in a neutral solution and turn blue in an alkaline solution.

Added:acidic: pH below 5.5 it turns (stays) redalkaline: pH above 8.0 it turns (stays) blueneutral, in between 5.5 and 8.0: its color is purple,between 'red and blue' or 'blue and red'

A much better indicator paper is universal indicator paper. It is yellow and can tell you the exact pH of the solution it is dipped in, going yellow to red in acidic conditions, blue to purple in alkaline conditions and green in neutral conditions. The exact colour depends on the pH.

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thank you my friend and a happy friendship day !

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Blue litmus paper stays blue in a neutral solution. It turns red only when in an acidic solution. Similarly, red litmus paper would stay red in a neutral solution and turn blue in an alkaline solution.

Added:acidic: pH below 5.5 it turns (stays) redalkaline: pH above 8.0 it turns (stays) blueneutral, in between 5.5 and 8.0: its color is purple,between 'red and blue' or 'blue and red'

A much better indicator paper is universal indicator paper. It is yellow and can tell you the exact pH of the solution it is dipped in, going yellow to red in acidic conditions, blue to purple in alkaline conditions and green in neutral conditions. The exact colour depends on the pH.

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same to you

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good question

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