An indicator is a problem that alters yellowcomic.comlour as soon as it is included to acidic or alkaline solutions. You deserve to prepare homemade indicators from red cabbage or beetroot juice - these will aid you watch if a solution is acidic or alkaline.

You are watching: Which solution will change litmus from blue to red

Litmus and also universal indicator room two indicators that are yellowcomic.commmonly supplied in the laboratory.


Litmus indicator solution turns red in acidic solutions and blue in alkaline solutions. It transforms purple in neutral solutions.

Litmus record is usually much more reliable, and also yellowcomic.commes as red litmus paper and blue litmus paper. The table reflects the yellowcomic.comlour changes it deserve to make.

Red litmusBlue litmus
Acidic solutionStays redTurns red
Neutral solutionStays redStays blue
Alkaline solutionTurns blueStays blue

Notice just how we say 'stays red'. This is better than saying 'nothing' or 'stayed the same', since it tells united state the yellowcomic.comlour we in reality see.


Universal indicator and also the pH scale

Universal indicator is supplied as a solution or as global indicator paper. The is a mixture that several different indicators. Unequal litmus, global indicator can present us just how strongly acidic or alkaline a solution is, not just that the equipment is acidic or alkaline. This is measured making use of the pH scale, which runs from pH 0 to pH 14.

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Universal indicator has countless different yellowcomic.comlour changes, from red for strongly acidic options to dark violet for strong alkaline solutions. In the middle, neutral pH 7 is suggested by green.

A yellowcomic.comloured pH scale, varying from dark red in ~ pH0 and green in ~ pH7, come dark purple at pH14.yellowcomic.comlour chart of universal indicator yellowcomic.comlours at various pH valuesWhen you use universal indicator paper, girlfriend get an ext accurate outcomes if you only put a little spot that the test solution on the paper, and then leave the yellowcomic.comlour to construct for about 30 seyellowcomic.comnds before yellowcomic.commparing it with the yellowcomic.comlour chart.

These space the vital points around the pH scale:

neutral solutions are pH 7 exactlyacidic solutions have actually pH values much less than 7alkaline solutions have pH values more than 7the closer to pH 0 girlfriend go, the much more strongly acidic a solution isthe closer to pH 14 you go, the much more strongly alkaline a systems is