CHEMISTRY (CLASS-10)
Time: 2:45 Hours | Total Marks: 60
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SECTION – A (Objective Type)
Marks: 12 | Time: 20 Minutes Note: Select the correct option for each question. Each part carries 1 mark.
1. When the rate of the forward reaction is equal to the rate of the reverse reaction, the state is called:1 (A) Static equilibrium (B) Dynamic equilibrium (C) Chemical completion (D) Irreversible state
2. The functional group –OH is characteristic of:2 (A) Ethers (B) Alcohols (C) Aldehydes (D) Ketones
3. What is the pH of a neutral solution at 25 °C?3 (A) 0 (B) 14 (C) 7 (D) 1
4. The percentage of nitrogen in Urea is:4 (A) 35.5% (B) 46.6% (C) 90.0% (D) 20.0%
5. Which of the following is a saturated hydrocarbon?5 (A) Ethene (B) Ethyne (C) Methane (D) Propene
6. The main component (about 85%) of natural gas is:6 (A) Ethane (B) Methane (C) Propane (D) Butane
7. Which gas is responsible for the “Greenhouse Effect”?7 (A) Nitrogen (B) Oxygen (C) Carbon dioxide (D) Argon
8. Permanent hardness in water is caused by the presence of:8 (A) Sodium chlorides (B) Calcium bicarbonates (C) Magnesium sulphates (D) Potassium nitrates
9. Which of the following is an example of a polysaccharide?9 (A) Glucose (B) Fructose (C) Sucrose (D) Starch
10. The purity of ‘blister copper’ is approximately:10 (A) 99.9% (B) 98% (C) 45% (D) 25%
11. The lowest layer of the atmosphere, extending up to 12 km, is the:11 (A) Stratosphere (B) Mesosphere (C) Troposphere (D) Thermosphere
12. Amino acids are the building blocks of:12 (A) Lipids (B) Carbohydrates (C) Vitamins (D) Proteins
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SECTION – B (Subjective Type)
Marks: 30 | Time: 2:25 Hours
Q2. Write short answers to any FIVE (5) of the following questions: (10 Marks)
1. Define Dynamic Equilibrium state.
2. Why do reversible reactions never go to completion?
3. What is the difference between a molecular formula and a structural formula?
4. Define catenation with an example.
5. List two characteristics of a homologous series.
6. Differentiate between essential and non-essential amino acids.
7. How do plants synthesize carbohydrates?
8. What is a peptide linkage?
Q3. Write short answers to any FIVE (5) of the following questions: (10 Marks)
1. Define Bronsted-Lowry acids and bases.
2. Give two limitations of the Arrhenius concept.
3. What is a neutralization reaction? Give an example.
4. Why are alkanes called paraffins?
5. How is ethene prepared by the dehydration of alcohols?
6. List the raw materials required for the manufacture of sodium carbonate by Solvay’s process.
7. Define metallurgy.
8. What is matte in the extraction of copper?
Q4. Write short answers to any FIVE (5) of the following questions: (10 Marks)
1. Name the major regions of the atmosphere.
2. How is acid rain formed?
3. Point out two serious effects of ozone depletion.
4. Differentiate between soft and hard water.
5. How is temporary hardness of water removed by Clark’s method?
6. Define waterborne diseases. Give one example.
7. What are boiler scales and how are they harmful?
8. Why is CO (Carbon Monoxide) considered a “hidden enemy” or health hazard?
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SECTION – C (Extensive Questions)
Marks: 18 | Attempt any TWO (2) questions.
Q5. (a) State the Law of Mass Action and derive the expression for the equilibrium constant (Kc) for a general reaction. (5 Marks)
(b) Explain the sources and uses of proteins in detail. (4 Marks)
Q6. (a) Describe the Lewis concept of acids and bases with examples of adduct formation. (5 Marks)
(b) Explain the fractional distillation of petroleum and describe any three of its important fractions. (4 Marks)
Q7. (a) What is acid rain? Describe its major effects on the environment and living organisms.(5 Marks)
(b) Describe the manufacture of Urea with the help of a flow sheet diagram. (4 Marks)
