Acids, Bases-10 PDF

Table 2.2 S. Solution Colour of Approx- Nature of Activity 2.11 No. pH paper -imate substance pH value n Test the pH va...

Table 2.2 S. Solution Colour of Approx- Nature of Activity 2.11 No. pH paper -imate substance pH value n Test the pH values of solutions given in 1 Saliva (before meal) Table 2.2. n Record your observations. 2 Saliva (after meal) n What is the nature of each 3 Lemon juice substance on the basis of your observations? 4 Colourless aerated drink 5 Carrot juice 6 Coffee 7 Tomato juice 8 Tap water 9 1M NaOH 10 1M HCl Figure 2.7 pH of some common substances shown on a pH paper (colours are only a rough guide) The strength of acids and bases depends on the number of H+ ions and OH– ions produced, respectively. If we take hydrochloric acid and acetic acid of the same concentration, say one molar, then these produce different amounts of hydrogen ions. Acids that give rise to more H+ ions are said to be strong acids, and acids that give less H+ ions are said to be weak acids. Can you now say what weak and strong bases are? 2.3.1 Impor tance of pH in Ever yday Life Everyday Are plants and animals pH sensitive? Our body works within the pH range of 7.0 to 7.8. Living organisms can survive only in a narrow range of pH change. When pH of rain water is less than 5.6, it is called acid rain. When acid rain flows into the rivers, it lowers the pH of the river water. The survival of aquatic life in such rivers becomes difficult. 26 Science 2024-25