Kathmandu BernHardt HS School
Balkhu, Kathmandu
First Term Examination-2070
Set: A
Faculty: Science
Subject: Chemistry
Grade: XII
Time: 3hrs
Group A
Attempt any fifteen questions:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
FM: 75
PM: 27
15x2=30
What is chromophore and auxochrome? Explain with examples.
Write the possible isomers of C3H7I with their IUPAC names.
What happens when ethanoic aid is reacted with MnO at 300°?
What is Williamson's synthesis of ether?
What happens when ethoxyethane is treated with excess of Cl2 in the
presence of light?
Identify the product in the following series of reaction:
An organic compound A having molecular formula C3H7Cl on
dehydrohalogination yields compound B. Compound so formed after
ozonolysis of B gives iodoform test. Identify A and B.
What happens when acetone reacted with hydrazine in the presence of
potassium hydroxide?
How do you prepare 2-methylpropan-2-ol by using Grignard's reagent?
Write the monomer of nylon-66 and Bakelite.
Can the absolute value of internal energy be determined? Why or why
not?
What are the conditions where H=E?
Give the sign conventions for work and heat?
The enthalpy change for the reaction
H2(g) + Cl2(g)
2HCl(g) at 25oC is –44 Kcal.
Find the internal energy change for this reaction at 25oC.
Define the concentration terms which are independent upon the
temperature.
What are the requisites for a substance to be primary standard?
What do you mean by degree of ionization? Why is it important in case of
weak electrolyte?
Classification of electrolyte into strong and weak is not scientific. Why?
What are transition elements? Give two examples.
What happens when ferrous sulphate crystals are exposed to air?
What is lithopone? How is it prepared?
21. What happens when 2 mole of formaldehyde reacts in presence of conc.
NaOH?
22. Define annealing and tempering of steel.
Group B
Attempt any five questions:
5x5=25
23. Write any five methods for preparation of aldehyde and ketones.
24. How do you convert a) 1-propanol to 2-propanol
b) ethanol to 2-methyl -2-propanol.
25. Write any three general methods of preparation of ethanoic acid?
26. Define semi-normal solution. To 50 mL of a solution of HCl ,25 mL of
0.82N NaOH solution were added. The excess of acid in the solution
required 30 mL of 0.99N Na2CO3 solution for neutralization. Calculate
the normality of the acid solution and number of gm of HCl per litre of
its solution.
27. Define enthalpy of reaction. State and explain Hess's law of constant
heat summation.
28. Derive Ostwald’s dilution law. Mention its limitation.
29. Describe the reduction of haematite?
Group C
Attempt any two questions:
10x2=20
30. Describe the laboratory method of preparation of chloroform. How
does it react with zinc dust and water?
31. a) Electrophillic substitution reaction on haloarenes.
b. A
Conc. H2SO4
170oC
Zn-Hg/HCl
i. CH3MgBr ii. H2O
B i. O3 ii. Zn/H2O C
D
E
Compound A is an alcohol which gives positive iodoform test and on
oxidation yields ethanoic acid. Identify A, B, C, D and E.
32. a) What are the postulates of Arrhenius theory of ionization? Define
strong and weak electrolyte.
b) i. A sample of Na2CO3 weighing 0.53 g added to 100 mL of 0.1N
H2SO4solution. Will the resulting solution be acidic, basic or neutral?
ii. A deci-molar solution of acetic acid is 1.3% ionized. Calculate
the ionization constant of acetic acid and also the pH of the
solution.
33.
Write short notes on (any two):2x5=10
a. Manufacture of steel by open hearth process b. Drugs
c. Distinguition of aldehyde and ketone. d. First law of themodynamics
Good Luck