1 Mark Questions
Q1. What is the pH of gastric juice, which is released during digestion.?
Q2. How does the flow of acid rain water into a river makes the survival of aquatic life in the river difficult?
Q3. Arrange the following in an increasing order of their pH values: NaOH solution, blood, lemon juice.
Q4. A solution has pH of 7. Explain how would you
(i) increase its pH
(ii) decrease its pH?
2 Mark Questions
Q5. A calcium compound which is a yellowish white powder is used as a disinfectant and also in textile industry.
(i) Name the compound
(ii) Which gas is released when this compound is left exposed to air?
Q6. What is meant by water of crystallisation? How would you show that copper sulphate crystals contain water of crystallisation?
Q7. A compound X of sodium is commonly used in kitchen for making crispy pakoras. It is also used for curing acidity in the stomach. Identify X. What is its chemical formula? State the reaction which takes place when it is heated during cooking.
3 Mark Questions
Q8. Account for the following:
(i) Antacid tablets are used by a person suffering from acidity.
(ii) Toothpaste is used for cleaning teeth.
(iii) Which acid is stinging hair of nettle leaves?
Q9. (i) A chemical compound X is used in glass and soap industry. Identify the compound and give its chemical formula.
(ii) How many molecules of water of crystallisation are present in compound X?
(iii) How will you prepare the above compound starting from sodium chloride? Write all relevant equations involved in the process.
Q10. How is plaster of Paris chemically different from gypsum? How can they be interconverted? Write two uses of Plaster of Paris.
5 Mark Question
Q11. (i) Define a universal indicator. Mention its one use.
(ii) Solution A gives pink colour when a drop of phenolphthalein indicator is added to it. Solution B gives red colour when a drop of methyl orange is added to it. What type of solutions are A and B and which one of the solutions A and B will have higher pH value.
(iii) Name one salt whose solution has pH more than 7 and one salt whose solution has pH less than 7.
Q12. A metal carbonate X on heating with an acid gives a gas which when passed through a solution Y gives the carbonate back. On the other hand, a gas G that is obtained at anode during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting drinking water. Identify, X, Y, G and Z.