General Instructions for Paper

Study Notes

Total Duration: 90 minutes
Maximum Marks: 40
Three sections in the question paper:
- Section A: 24 questions, attempt any 20
- Section B: 24 questions, attempt any 20
- Section C: 12 questions, attempt any 10
Equal marks for all questions, no negative marking.

Reaction: H2S(g) + Cl2(g) → 2HCl(g) + S(s)
- Interpretation: H2S gets oxidized, Cl2 gets reduced.
Aqueous solution changes red litmus to blue; reversing the change can be achieved by adding:
- Hydrochloric acid.
Identifying covalent compounds:
- Carbon tetrachloride is covalent in nature.
Reaction coefficients in combustion: C3H8 + xO2 → yCO2 + 2H2O
- Correct coefficients: p=1, q=5, r=3, s=4.
Alum classification:
- Alum is a double salt.
An element reacting with oxygen to form a water-soluble compound with a high melting point:
- Calcium is a likely candidate.
Decomposition products:
- Incorrect match: H2CO3 decomposes into H2 (not a typical gaseous product).
Properties of ionic compounds:
- Ionic compounds form crystals, are very brittle, have high melting points, and conduct electricity when melted.
Kinetic reaction changes with KHCO3:
- Statement that is not correct: Lime water will turn milky.
Reducing agent properties of hydrogen sulfide (H2S):
- Reducing action illustrated by the reaction: CuSO4 + H2S → CuS + H2SO4.