Question

Dip a piece of red and a piece of blue litmus paper in each of the solution to be tested. Note the colour change observed in the following table:

Sl.No.	Name of the material	Colour of the blue litmus	Colour of the red litmus
$1$	Soap solution
$2$	Tamarind juice
$3$	Curd
$4$	Sodium hydroxide solution
$5$	Lime water
$6$	Baking soda solution
$7$	Orange juice

Accepted Answer

Soap solution is basic in nature. Therefore, blue litmus remains as it is and red litmus changes to blue.

Tamarind juice is acidic in nature due to the presence of tartaric acid. Therefore, red litmus remains as it is and blue litmus changes to red.

Curd as lactic acid hence red litmus remains as it is and blue litmus changes to red.

Sodium hydroxide is a basic solution. Therefore, blue litmus remains as it is and red litmus changes to blue.

Lime water is the aqueous solution of calcium hydroxide. It is a basic solution. Therefore, blue litmus remains as it is and red litmus changes to blue.

Baking soda (sodium bicarbonate) solution is a basic solution. Therefore, blue litmus remains as it is and red litmus changes to blue.

Orange juice contain citric acid. In acidic solution red litmus remains as it is and blue litmus changes to red.

The colour change observed in the following table:

Sl.No. Name of the material Colour of the blue litmus Colour of the red litmus

$1$ Soap solution Blue Blue

$2$ Tamarind juice Red Red

$3$ Curd Red Red

$4$ Sodium hydroxide solution Blue Blue

$5$ Lime water Blue Blue

$6$ Baking soda solution Blue Blue

$7$ Orange juice Red Red

West Bengal Board Solutions for Chapter: Role of Substances in Environment, Exercise 21: Exercise 21

West Bengal Board Science Solutions for Exercise - West Bengal Board Solutions for Chapter: Role of Substances in Environment, Exercise 21: Exercise 21

Questions from West Bengal Board Solutions for Chapter: Role of Substances in Environment, Exercise 21: Exercise 21 with Hints & Solutions

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