`CHEMISTRY
Paper – 1
(Theory)
Three hours and a quarter
(The first 15 minutes of the examination are for reading the paper only.
Candidates must NOT start writing during this time)
………………………………………………………………………………
Answer all questions in Part I. From part II, answer any four questions from
Section A, any three questions from Section B and any two questions from
Section C
All works including the rough work, should be done on the same sheet as, and
adjacent to the rest of the answer in the answer booklet
The intended marks for questions are given in brackets [ ]
Balanced equations must be given wherever possible and diagrams where they
are helpful
When solving numerical problems, all essential working must be shown
In working out problems, use the following data:
Gas constant R = 1.987cal deg-1 mol-1 = 8.314 JK-1 mol-1 = 0.0821dm3 atm K-1
mol-1
PART I (40 MARKS)
Answer all the questions
Question no 1
A Correct the following statements
[5]
1) When dilute solution of sodium cyanide is added to silver chloride solution,
silver is precipitated
2) Tartaric acid exhibits both geometrical isomerism and structural isomerism
3) Poly ethylene is a natural polymer formed by condensation polymerization
4) For water system the number of phases that can exist in equilibrium is one
5) Aqueous solution of sodium acetate is neutral
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B) Fill in the blanks choosing appropriate word/s given in the brackets. Write
the correct answers in your answer booklet.
[5]
[less, one , first order, equal , more , greater, acetaldehyde , acetic acid , two ,
second order , formaldehyde , four , three , sum , zero order , greater]
1) Cannizzzaro reaction is shown by ……………….
2) When an element loses an alpha particle and a beta particle, its atomic
number decreases by ………………. Unit/s and its atomic mass
decreases by ………………. Unit/s
3) Aniline is …………………………… basic than ammonia
4) When two liquids form an ideal solution, the vapour pressure of the
solution is …………. the ……………. of the partial vapour pressure of
the two liquids
5) The half life period of a………………… reaction do not depend on the
concentration of the reactants
C) Each question below is followed by four possible choices of answers.
Choose the correct answer and write it in your answer booklet
[5]
1. From hexamethylene diamine and adipic acid nylon is prepared, which of
the following statements is not true
i.
ii.
iii.
iv.
Synthetic polymer
Condensation polymer
Co – polymer
Addition polymer
2. Entropy is expressed as
i. Calories
ii.
Calories deg-1
iii. Calories deg-1mole-1
iv. Calories mole-1
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3. The bond order in N2+ is
i.
ii.
iii.
iv.
1
2
2.5
3
4. The osmotic pressure of 5% solution of cane sugar at 1500C is
i.
ii.
iii.
iv.
3.40 atm
5.07 atm
2.09 atm
4.03 atm
5. Half life period of a radioactive substance is 120 days. After 480 days, 4 g
wil be reduced to
i.
ii.
iii.
iv.
2
1
0.5
0.25
6. Distribution law is given by
i.
ii.
iii.
iv.
Raoult
Nernst
Van’t hoff
Le chatilier
7. Ammonia dissolves in water to give ammonium hydroxide. In this water act
as
i.
ii.
iii.
iv.
Conjugate acid
Acid
Conjugate base
Base
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8. Silver is refined by cupellation process. The process removes the impurity of
i.
ii.
iii.
iv.
Copper
Gold
Platinum
Lead
9. H2S on complete combustion forms mainly
i.
ii.
iii.
iv.
Sulphur and water
Sulphur dioxide and water
Hydrogen and sulphur
Sulphur dioxide and hydrogen
10.A buffer solution is a mixture of
i.
ii.
iii.
iv.
A strong acid and a weak base
A weak acid and strong base
Strong acid and its salt with weak base
Weak acid and conjugate base
D) Match the items of column A with the items in column B. Rewrite the
correct pairs in your answer booklet
[5]
Column A
Aldol
Bronsted
Cannizzaro
Faraday
Wholer
BHSEC/Trial chemistry 2010/JSHSS
Column B
Glycine
Acetic acid
Urea
Benzaldehyde
Acid and base
Distribution law
Laws of electrolysis
Acetaldehyde
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E) Answer the following questions. Each question carries TWO marks
1. Sucrose does not reduce silver nitrate but when pretreated with dilute acids it
does reduce
2. A radio isotope of phosphorus 15 P32 emits beta rays
a. What are the atomic number and mass number of the isotope?
b. What are the mass number and atomic number of the product formed?
3. Draw the electron dot formulae of sulphuric acid clearly distinguishing
between the electrons of each atom
4. Name a compound which exhibits tautomerism. Draw the structure of the
tautomers
5. What do you understand by the term unit cell with reference to crystals?
6. Why does water taken to the top of the mountain less dissolved air than
water kept in the plains at the foot of the mountain. What law governs this
phenomenon?
7. What is the principle on which paper chromatography is based?
8. The rate constant of a first order reaction is 2.31x10-2 sec-1. What will be
the time required for the initial concentration of 0.1M of the reactant to be
reduced to 0.05M
9. If the value of faraday is 120460 coulombs, what will the charge of the
electron?
10.What happens when iodine is added to sodium thiosulphate solution
PART II
SECTION A
Answer any four questions [28 marks]
Question 2
1. Explain the following with an example
a. Co – ordinate bond
[2]
b. Hydrogen bond
2. What do you understand by lattice structure of a crystalline substance?
Explain why diamond is hard and graphite is soft
[2]
3. State Henry’s law for solubility of gases in liquids. Explain it in terms
of Le Chatilier’s theorem
[2]
0
4. An aqueous cane sugar solution freezes at -0.372 C. Calculate the
molality of the solution. [The cryoscopic constant of water
is1.86Kmol-1kg-1]
[1]
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Question 3
1. At 270C a first order reaction is 50%in 30 minutes. Calculate the
specific rate constant at 270C
[1]
2. Draw the graph which can be used to measure the activation energy of
a reaction
[2]
3. Explain the following
a. An aqueous solution of sodium acetate is basic
[2]
b. In acidic medium dissociation of hydrogen sulphide is
decreased
[2]
Question 4
1. A solution to be used in a hand lotion is prepared by mixing 90.0gms of
water, 9.2gms of ethyl alcohol and 18.4gms of glycerol. Calculate the mole
fraction of glycerol.
[Water – H2O
ethyl alcohol – C2H5OH
glycerol C3H8O3]
[2]
2. Calculate the equivalent conductivity of 1Msulphuric acid whose specific
conductivity is 26x10-2ohm-1cm-1
[2]
131
32
3. Give one use of I and P radio isotopes
[1]
4. Give suitable reason for the following
a. Graphite is anisotropic with respect to the conduction of electricity[1]
b. Chlorine does not form hydrogen bond
[1]
Question no 5
1. The solubility product of AgCl in water is 1.5x10-10. Calculate its solubility
in 0.01M aqueous NaCl solution
[2]
3
2. 10gms of an organic compound was present in 100cm of water. It was
extracted twice with 50 cm3 portions of ether. How much organic compound
was extracted? The organic compound is three times more soluble in ether
than in water
[2]
3. In a simple electrochemical cell, the reduction reactions are
a. Pb2+ + 2e
b. Ag+ + e
→ Pb
→ Ag
E0 = -0.13V
E0 = 0.80V
Write the cell reaction and calculate the emf of the cell
[1.5]
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4. What are moderators and control roads? Mention their functions in the
nuclear reactor
[1.5]
Question no 6
1. The standard reduction potential of Cu2+/Cu and Zn2+/Zn is 0.350V and 0.763V respectively.
a. Construct a galvanic cell using the above electrodes so that its emf is
positive
b. Calculate the emf of the cell
[3]
c. Write the cell reaction
2. Which of the two is considered to be more stable O2+ or O2-? Justify your
answer
[2]
3. What are the two basic principles applied in chromatography
[1]
4. Differentiate between true solution and colloidal solution based on optical
activity
[1]
SECTION B
Answer any three questions [18 marks]
Question no 7
1. How does silver occur in nature? Give an outline of its extraction from its
sulphide ore by the cyanide process
[4]
2. What change do you observe when dilute hydrochloric acid followed by
sodium thiosulphate solution is added to silver nitrate solution? Explain the
chemical change
[2]
Question no 8
1. Mention two important physical properties of bromine
[1]
2. What is the action of bromine water on?
a. Potassium iodide solution
b. Hydrogen sulphide solution
[2]
3. One mole of a gas is allowed to expand isothermally and reversibly from a
volume of 1dm3 to 50 dm3 at 00C. Find the work done, internal energy
change and heat absorbed assuming ideal behavior of the gas
[3]
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Question no 9
1. What are alums? Mention two uses of potash alum
2. Define and distinguish between electromeric and inductive effect
3. Explain SN1 mechanism with an example
[2]
[2]
[2]
Question no 10
1. How colloidal solution of arsenic sulphide is prepared
[1]
2. How iodine is manufactured from sea weeds
[2]
3. Calculate the free energy change for the reaction
H2 (g) + I2 (g) → 2HI at 298K. The standard enthalpy change and
standard entropy change for the reaction are 52.0 Kj and 165.2kj
respectively
[3]
SECTION C
Answer any two questions [14 marks]
Question no 11
1. Write a balanced equation for the following reactions. What do you observe
in each case?
a. Glucose is reacted with Tollen’s reagent
[1]
b. Fructose is treated with excess phenyl hydrazine
[1]
2. How many tartaric acids are known? Write the structure of optically inactive
tartaric acid
[2]
3. How phenol is prepared from chlorobenzene?
[1]
4. Explain the following with at least one example
a. Keto – enol tautomerism
b. Williamson’s synthesis
[2]
Question no 12
1. Give a chemical test to distinguish between
a. Cellulose and starch
b. Benzaldehyde and acetaldehyde
[2]
2. Write all the isomers of the compound with molecular formulae C3H6O [2]
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3. A compound X having the molecular formulae C2H7N on treatment with
nitrous acid gave a compound Y having the molecular formulae C2H6O. The
compound Y on treatment with acetyl chloride gave a compound Z with
molecular formulae C4H8O2.
a. Name the compound X, Y and Z
b. Write a balanced equation for the formation of Y
[3]
Question no 13
1. Write a balanced equation for the following
a. Glycine with nitrous acid
b. Action of heat on urea
[2]
2. Name the monomers of the following
a. Darcon
b. Teflon
[1]
3. Differentiate between co polymer and homo polymer. Give suitable example
for each
[1]
4. Write a balanced chemical equation for the following
a. Benzaldehyde with hydroxyl amine
b. Phenol reacts with bromine water
[3]
c. Benzoic acid treated with a mixture of concentrated nitric acid and
concentrated sulphuric acid
ALL THE BEST
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