Strength of acid and base:pH Scale

By | July 21, 2016

Question 1 What does pH of a solution signify?

Question 2 You have 2 solutions A and B.The pH of solution A is 6 and pH of solution B is 8.Which of the solution has more hydrogen ion concentration?

Question 3 Three solutions A,B and C have pH values of 6,4 and 10.Which of the solution is highly acidic?

Question 4 The pH of a solution is 5.What will be its action on blue and red litmus?

Question 5 Name the scientist who discovered pH scale?Question 6 Two solutions A and B  have pH values of 3 and 9.Which will turn phenolphthalein from colourless to pink?

Question 7 What is the pH of neutral solution?

Question 8 Fresh milk has a pH of 6>how do you think the ph would change as it turns into curd?

Question 9 What effect does the concentration of hydrogen ion have on nature of the solution?

Strength of acid and base: pH Scale

In pure water  [H+] = [OH]

1) Pure water + acid(produce H+) ——-> Concentration of hydrogen ion(H+) increasesSolution will have more of hydrogen ion(H+).

2) Pure Water + base (Produce OH-)———>Concentration of OH- increases Solution will have more of OH- ions.

In 1909 Sorenson gave a scale known as pH scale.The strength of an acid as well as basic solution can be represented by making use of Hydrogen ion concentration (H+)in them.The pH of a solution is inversely proportional to hydrogen ion in it.High the concentration of hydrogen ion lower will be its pH.Lower the concentration of hydrogen ion Higher will be its pH.

P represents potenz means power whereas H represents concentration. 

The strength of an acid or base is measured on a scale of numbers called pH scale (0-14)

1) Neutral Solution


2) Acidic Solution


More acidic a solution is lesser will be its pH.

Solution with pH=0,1,2,3 are strong acids.

Solution with pH=4,5,6 are weak acids.

Lower the pH stronger will be the acid. 

3) Basic solution


More basic a solution is more will be its pH.

Solution with pH=8,9,10 are weak base.

Solution with pH=11,12,13,14 are strong base.

Higher the pH,stronger will be a base. 

pH scale
Blood pH=7.4
Conc HCl pH=1
Conc NaOH pH=14

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