What are Acid Base indicators

An Acid Base Indicator is a substance that give different colours in acidic and basic media.

Litmus, Turmeric, Red cabbage and China-rose - give different colours in acidic and basic media.

Litmus: It is obtained from certain litchens (small plants)-it turns red in acidic and blue in basic solution.

Litmus paper is a finger sized strip of paper which is soaked in the litmus solution and dried. It is convenient to work with as it also turns red in acidic and blue in basic solution.

Phenolphthalein: A dilute solution of Phenolphthalein (a colourless chemical) turns red or pink in basic solution and is colourless in acidic and neutral media.

Turmeric Juice: The yellow turmeric juice turns reddish or deep brown in basic media and remain yellow in acidic or neutral media.

If a white piece of cloth is dipped in aqueous solution of turmeric , It becomes yellow . If it is washed with a soap , instead of becoming white again the cloth becomes red or brown. If it is washed with water , it becomes yellow again. Soap is basic so it turns turmeric red or brown but when the soap solution is washed the turmeric regains its yellow colour.

China rose juice turns green in basic medium and red in acidic solution.

Red cabbage juice is purple in colour turns green in basic medium and red in acidic solution.

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The grandfather's House

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Reading comprehension 1

Read the following passage carefully and answer the questions that follow: Theodoric had been brought up by his mother, screening him from the hard realities of life. When she died she left Theodoric alone in a world that was as real as ever. He had been staying at a country vicarage, the inmates of which had been certainly not brutal. On a particular day he set out on a journey by train. The pony carriage that was to take him to the station had never been properly ordered; and when the moment for his departure drew near, The handy man who should have helped him was no where to be found. In this emergency Theodoric found himself obliged to collaborate with the vicar daughter in the task of harnessing the pony which necessitated groping about in and ill-lighted stable which smelt of mice. As the train gilded out of the station, Theodoric's clothes were giving out an odour of mice. The only other occupant of the compartment, a lady of about the same age as himself seem...

CBSE-ICSE- language skills - composition - comprehension skills-Soft skills training

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