Chemistry | Grade 12-XII | Model Question Paper | 2077-2020 | Subject Code-212 | NEB | Download in PDF

NATIONAL EXAMINATIONS BOARD [NEB]

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'

Attempt any five questions. (5x2=10)

1. Write two important features of hybrid orbitals. (2)

2. Define the terms: (1+1)

i) Primary standard solution

ii) Acidimetry

3. How many coulombs are required to produce 50 gm. of Al when electrode reaction is

Al++++ 3e Al (atomic mass of Al = 27). (2)

4. For a reaction,

2N2O54NO2+O2, The rate of disappearance of N2O5 is 4x10-6 mol L-1S-1, what will be the rate of formation of NO2? (2)

5. Write the action of heat on blue vitriol. (2)

6. Write an example of each of the following. (1+1)

i) Aldol Condensation

ii) Rosenmund's reduction

7. Write down the structure of a primary amine and a secondary amine from C3H9N and give their IUPAC name. 1+1

Group 'B'

Attempt any two questions. (2x5=10)

8. Define the terms:

i) titration error

ii) unknown solution

What volume of 10 M HCl and 3 M HCl should be mixed to obtain one litre of 6 M HCl solution. (1+1+3=5)

9. State enthalpy of combustion.

If heat of formation of CO2, H2O and C6H12O6 are -395 KJ mol-1, -269.4 KJ mol-1 and 1169 KJ mol-1 respectively. Calculate the heat of combustion of glucose. (1+4=5)

10. Give chemical reaction for the preparation of ethanoic acid from

i) 1, 1, 1-trichloro ethane

ii) Methyl magnesium iodide

iii) ethane nitril.

How is ethanoic acid converted into methanoic acid? (3+2=5)

Group 'C'

Attempt any one question. 1x10=10

11. Write down a structural formula and its IUPAC name of C4H10O. How would you apply Victormayer's method for the distinction of propan-1-ol from propan-2-ol? Write an example of the following reactions.

i) oxo-process

ii) Baeyer's test

Convert propan-2-ol into propan-1-ol. (2+4+2+2=10)

12. Define:

i) rate law equation

ii) Half life period for a reaction

How is order of a reaction differed from molecularity of reaction?

The following rate data were obtained for the reaction 2A+BC

Expt No. [A] mol L-1 [B] mol L-1 initial rate of formation of C mol L-1 S-1

1 0.1 0.1 6.0x10-3

2 0.3 0.2 7.2x10-2

3 0.3 0.4 2.88x10-4

4 0.4 0.1 2.4x10-2

Calculate the rate of formation of C when [A] = 0.5 mol L-1 and B = 0.2 mol L-1. (2+4+4=10)

View and download the Chemistry Grade 12-xii Model Question Paper of the year 2077-2020 with subject code-212 neb containing fullmarks 30.

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