Chemistry (Chem) NEB 2074 (old course) Question Paper – +2 Science Class 11

Chemistry NEB 2074 (old course) question paper

33 questions · 33 with worked answersSit this paper (timed)

National Examinations Board (+2)

+2 Science (Class 11 and 12)

Class 11 · NEB 2074 (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.
How many number of oxygen molecules are required to produce 220 mg of $CO X_{2}$ according to the reaction? $C + O X_{2} CO X_{2}$

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2
2.
State Gay-lussac's Law of gaseous volume.

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2
3.
Give proper reason for the followings. i) Evaporation takes place from the surface of liquid. [1] ii) Liquid drops are spherical shape. [1]

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2
4.
Differentiate between hygroscopic and deliquescent substances giving an example of each.

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2
5.
What information is provided by the magnetic quantum number? Give the values of $l$ and $m$ for $3 P_{x}$ orbital. [1+1]

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2
6.
Calculate the atomic number and number of p-electrons of an atom whose valence shell electronic configuration is $4 S^{2}$ .

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2
7.
What is meant by controlled nuclear fission? Mention its an important application. [1+1]

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2
8.
Write down the Lewis structure of [1+1] i) $N X_{2} O$ ii) $HClO X_{4}$

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2
9.
How would you explain the polarity of a molecule on the basis of dipole moment?

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2
10.
Which ion would you expect to have larger size and why? $Mg X^{++}$ or $Na X^{+}$

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2
11.
Calculate the oxidation number of [1+1] i) N in $NH X_{4} OH$ ii) Cr in $K X_{2} Cr X_{2} O X_{7}$

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2
12.
Write the relationship between Kp and Kc for the reaction [1+1] i) $PCl X_{5} (g) PCl X_{3} (g) + Cl X_{2} (g)$ ii) $N X_{2} (g) + 3 H X_{2} (g) 2 NH X_{3} (g)$

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2
13.
Which one is the least abundant isotope of hydrogen. Mention its two uses. [1+1]

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2
14.
Suggest your ideas to protect Ozone layer from its depletion.

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15.
Give a balanced chemical reaction for the preparation of CO in the laboratory. Why is CO harmful gas? [1+1]

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2
16.
Write down the molecular formula and an use of each of the followings [1+1] i) Boric acid ii) Orthophosphoric acid

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2
17.
What is meant by Slag? Write an example of it.

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18.
What happens when [1+1] i) Bleaching powder is treated with $dil \cdot H X_{2} SO X_{4}$ ii) Gypsom salt is heated above $13 0^{\circ} C$ .

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2
19.
Write down IUPAC name of the following organic compounds. [1+1] i) $CH X_{3} - O - CH X_{2} - CH X_{2} - OCH X_{3}$ ii) $CHCl X_{3}$

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2
20.
Write reactions for the preparation of Methane from [1+1] i) $CH X_{3} MgBr$ ii) $CH X_{3} COONa$

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2
21.
Identify the major product $\overset{◯}{A}$ and $\overset{◯}{B}$ in the following reaction sequence. [1+1] $CaC X_{2} H X_{2} O \overset{◯}{A} ammonical AgNO X_{3} \overset{◯}{B}$

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2
22.
Give functional isomers of ethanoic acid and propanone with their structural formula.

GROUP: B | Short answer questions | 5 × 5 = 25

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2

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