1. What is common to all acids? (1 mark) 2. A white chemical compound becomes hard on mixing proper quantity of water. It is also used in surgery to maintain joins in a fixed position. Name the chemical compound. (1 mark) 3. Name two constituents of baking power. (1 mark) 4. A farmer has found that the pH of soil in his fields is 4.2. Name any two chemical material which he can mix the soil to adjust its pH. (1 mark) 5. Write the pH value, after which teeth start decaying? (1 mark) 6. How is the concentration of hydroxide ions (OH-) affected when excess base is dissolved in a solution of sodium hydroxide? (2 marks) 7. A white substance having a strong smell of chlorine is used to clean water in water storage tank. Identify the substance. Write its chemical name and the reaction for its preparation. (2 marks) 8. How is plaster of Paris obtained? What reaction is involved in the setting of a paste of plaster of Paris. (2 marks) 9. Name the gas evolved when dilute sulphuric acid acts on s...