Activity 2.11 Class 10 Science

In this activity, we will test various solutions using `P^H` paper to determine their `P^H` value and classify them as acidic, basic or neutral.

What is the nature of the solutions on the basis of the `P^H` value?

 

Aim of the activity

 

To find the `P^H` value of different solutions and determine the nature of the solutions

 
Materials used in the activity

 

S.N.	Materials
1	Dropper
2	`P^H`   paper
3	Beaker
4	Various solutions

 

Procedure

 

We take clean `P^H` paper strips and put a drop of the given solutions one by one on separate `P^H` papers and observe the colour change.

We match the colour with the standard `P^H` chart to determine the `P^H` value.

We also identify the nature of each solution based on the `P^H` scale.

Table

S. No.	Solution	Colour of pH paper	Approximate pH value	Nature of substance
1 2 3 4 5 6 7 8 9 10	Saliva (before meal) Saliva (after meal) Lemon juice Colourless aerated drink Carrot juice Coffee Tomato juice Tap water 1M NaOH 1M HCI

 

Observation Table

S. No.	Solution	Approximate pH Value	Nature of substance
1 2 3 4 5 6 7 8 9 10	Saliva Lemon juice Colourless aerate  drink Carrot juice Coffee Tomato juice Tap water 1 M NaOH 1 M HCI	6.5 to 7.5 2.2 to 2.4 5.9 to 6.0 6.4 to 6.6 4.5  to 5.5 4.1 6.9 to 7 14 0	Neutral Acidic Acidic Acidic Acidic Acidic Neutral Basic Acidic

Explanation

1. Substances with a `P^H` less than 7 are acidic.

2. Substances with a `P^H` greater than 7 are basic.

3. Substances with a `P^H` of 7 are neutral.

4 .Strong acids like HCl have `P^H` value of 0, and strong bases like NaOH have `P^H` value of 14.

 

Conclusion

This activity helps to classify the substances into acidic, basic or neutral based on `P^H` values.

 

Multiple Choice Questions

1.   What is the `P^H` value of a neutral solution?

   a)     Less than 7   

   b)     More than 7

   c)       7

   d)      None of these

Correct answer – (c) 7

2.  What is the P^H` of lemon juice?

    a)    4  -  6

    b)    2  -  3

    c)  8  -  9

    d)   11-12

Correct answer – (b) 2-3

3.    If a solution or substance shows purple colour on `P^H` paper is

   a) Strong acidic

   b)   Strong basic

   c) Neutral

   d)  None of the above

Correct answer – (b) strong basic

4.  What is the `P^H` of distilled water?

    a)  5

    b)    7

    c)  8

    d)     6.5

Correct answer – (b) 7

5.       Which substance is more acidic?

    a)  5

    b)     4

    c)  6.5

    d)   2.5

Correct answer – (d) 2.5 

Related Topics -

1. Activity 2.12

2.  Activity 2.10

2. Solutions of Chapter 2 

3. MCQ Questions of Chapter 2

4. Extra Questions of Chapter 2