National Examinations Board (+2)
+2 Science (Class 11 and 12)
Class 12 · NEB 2076 (old course)
Course Title: Chemistry (Chem)
Full Marks: 75Pass Marks: 27Time: 3 hrs
Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
Group A
Very short answer questions(15 × 2 = 30)
- 1.2
C in gets SP hybridization, why?
- 2.2
Distinguish between titration error and normality factor.
- 3.2
Write the conjugate acid and base of .
- 4.2
How many coulombs are required to produce i) 80gm of calcium from molten ? [1] ii) 50gm of Aluminum from molten ? [1]
- 5.2
State the first law of thermodynamics.
- 6.2
Calculate entropy change () and free energy change () for the conversion of ice into water at equilibrium when enthalpy change () is .
- 7.2
You are given a rate law equation . By how many times will the rate increase or decrease for the reaction if i) concentration of is doubled while that of remain constant. [1] ii) Concentration of is kept constant that of is doubled? [1]
- 8.2
How is sodium benzoate converted into acetophenone?
- 9.2
Explain, why is chlorobenzene less reactive than benzene in electrophilic substitution reaction?
- 10.2
What product would you obtain when phenol is treated with i) Benzene diazonium chloride? [1] ii) Phthalic anhydride? [1]
- 11.2
Identify the major products and giving their IUPAC names in the given reaction sequence.
- 12.2
An organic Compound does not give silver mirror with tollen's reagent but gives yellow precipitation with and . Identify the compound and write the reactions involved.
- 13.2
Why is nitro group called an ambident group?
- 14.2
What happens when aniline is i) treated with benzene diazonium chloride. [1] ii) heated with chloroform in presence of . [1]
- 15.2
Write down the functional isomer of methyl methanoate, what product would you expect when the isomer is heated with ?
- 16.2
What are lipids? Name the products formed when simple lipids undergo hydrolysis.
- 17.2
What is meant by i) invert sugar and ii) non-reducing sugar.
- 18.2
Mention an important function of each of the following: i) DDT ii) Nitrogen fertilizer iii) tranquilizers iv) broad spectrum antibiotics.
- 19.2
Name the monomers of backelite and state the polymerisation process of it.
- 20.2
How is granulated zinc obtained? Write its an important application.
- 21.2
Why is silver nitrate solution used for staining fingers of voters during election?
- 22.2
What is meant by i) quenching of steel. ii) annealing of steel.
GROUP: B | Short answer questions | 5 × 5 = 25
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