Class 12 Model Questions (Chemistry)

NEB – GRADE XII
Chemistry
Model Question [2077(2020)]
Candidates are required to give their answers in their own words as far as
practicable. The figures in the margin indicate full marks.
Time: 1.30 hrs. Full Marks: 30
Group ‘A’
Attempt any five questions. 5×2=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 4×10-6 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. 2×5=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
   Sub.Code : 212
   Contd…
   212 (2)
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
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
    Group ‘C’
    Attempt any one question. 1×10=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
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 6.0×10-3
    2 0.3 0.2 7.2×10-2
    3 0.3 0.4 2.88×10-4
    4 0.4 0.1 2.4×10-2
    Calculate the rate of formation of C when [A] = 0.5 mol L-1 and
    B = 0.2 mol L-1. 2+4+4