SSLC EXAMINATION, MARCH - 2025
CHEMISTRY (English)
Time: 1½ Hours
Total Score: 40
Instructions:
- The first 15 minutes is cool-off time.
- You may use this time to read the questions and plan your answers.
- Answer only on the basis of instructions and questions given.
- Consider score and time while answering.
SECTION - A
Answer any 4 questions from 1 to 5. Each question carries 1 score. 4x1=4
1. Which of the given compounds is a mineral of Aluminium?
(Calamine, Cuprite, Cryolite, Magnetite)
Answer - Cryolite
12. Which polymer is formed from isoprene?
Answer: Natural Rubber
13. Find the total number of atoms in 2 GMM water (H₂O).
Answer : GMM (gram molecular mass) of water (H2O) = 18g 1 molecule of H₂O contains 3 atoms (2 hydrogen + 1 oxygen) mole of H2Ocontains (6.022 × 1023) molecules
14. Which is the product obtained when SO₃ gas is dissolved in concentrated sulphuric acid?
Answer: Oleum (H2S3O7)
15. Many of the metals in ______ block are used as catalysts in petroleum industry.
(s, p, d, f)
Answer: d-block
1SECTION - B
Answer any 4 questions from 6 to 10. Each question carries 2 scores. 4x2=8
6. Classify the following compounds into alkanes, alkenes and alkynes.
C₂H₄, C₅H₁₂, C₃H₈, C₆H₁₂
Answer Alkanes: C5H12(Pentane), C3H8(Propane)
Alkenes: C2H4 (Ethene), C7H12 (Heptene)
Alkynes: (None in the given list)
27. Two gases Oxygen and Nitrogen at STP are given.
(a) Calculate the number of molecules in 64 g of Oxygen.
Answer Molecular mass of O2 = 32g 1 mole of O2 = 6.022 ×10 23 molecules Moles in 64 g O2 = 64/32 = 2 moles Total molecules = 2 × 6.022 × 10 23 =1.204×10 24 molecules
(b) Calculate the mass of Nitrogen having the same volume as that of 64 g of Oxygen.
At STP, equal volumes of gases contain equal moles.
64 g of O22= 2 moles
For N2 2 moles = 2 x 28 g = 56 g
Answer: Mass of Nitrogen = 56 g
1 18. Two reactions related to the extraction of metals are given. Among these reactions, identify calcination and roasting.
(a) Cu₂S ore is converted to Cu₂O by heating.
Answer: Roasting (since Cu₂S reacts with oxygen)
b) Carbonates and hydroxides of metals decompose to form their oxides.
Answer: Calcination (since it involves thermal decomposition without oxygen)9. Identify A and B.
(a) CH3-OH + CO (A) (in presence of catalyst, high temperature & pressure)
Answer: A = CH3COOH (Acetic Acid)(b) CHCl3 + Cl2 → (B) + HCl
Answer: B = CCl4 (Carbon Tetrachloride)