1st Year Lahore Board 2013
Chemistry – Paper I
Time Allowed: 20 Minutes
(Objective Type)
Group – I
Max. Marks: 17
NOTE: Four answers are given against each question in columns A, B, C and D. Select the right
answer and on the separate Answer Sheet, fill the circle A, B, C or D with pen or marker in
front of that question number.
1.
2.
3.
4.
Which statement is not true?
(A) Isotopes with even atomic masses are comparatively abundant.
(B) Isotopes with odd atomic masses are comparatively abundant.
(C) Isotopes even atomic masses and even atomic numbers are comparatively abundant
(D) Isotopes with even atomic masses and odd atomic numbers are comparatively abundant.
27 g of Al will react completely with how much mass of O2 to produce Al2O3?
(A) 8g of oxygen
(B) 16g of oxygen
(C) 32g of oxygen
(D) 24g of oxygen
Solvent extraction method is particularly useful technique for separation when the product to the
separated is:
(A) Non-volatile or thermally unstable
(B) Volatile or thermally stable
(C) Non-volatile or thermally stable
(D) volatile or thermally unstable
3
Number of molecules in one dm of water is close to:
(A)
5.
6.
7.
8.
9.
10.
11.
6.02
1023
22.4
12.04
1023
22.4
(C)
18
1023
22.4
(D) 55.6 × 6.02 × 1023
London dispersion forces are the only forces present among the:
(A) Molecules of water in liquid state
(B) Atoms of helium in gaseous state at high temperature
(C) Molecules of solid iodine
(D) Molecules of hydrogen chloride gas
The molecules of CO2 in dry ice form the:
(A) Ionic crystals
(B) Covalent crystals (C) Molecular crystals (D) Any type of crystals
Quantum number value for 2t orbitals are:
(A) n = 2, l = 1
(B) n = 1, l = 2
(C) n = 1, l = 0
(D) n = 2, l = 0
The nature of positive rays depends on:
(A) The nature of electrode
(B) The nature of discharge tube
(C) The nature of residual gas
(D) The temperature
An ionic compound A * B is most likely to be formed when:
(A) The ionization energy of A is high and electron affinity of B low
(B) The ionization energy of A is low and electron affinity of B high
(C) Both the ionization energy of A and electron affinity of B are high
(D) Both the ionization energy of A and electron affinity of B are low
Formation of chemical bond takes place when:
(A) Energy is absorbed
(B) Forces of repulsion overcome forces of attraction
(C) Forces of attraction are equal to forces of repulsion
(D) Forces of attraction overcome forces of repulsion
For a given process the heat changes at constant pressure (q p) and the constant volume (qv) are
related to each other as:
(A) qp = qv
12.
(B)
(B) qp < qv
(C) qp > qv
Which statement about the following equilibrium is correct:
2SO2( g )  O2( g )
2SO3( g )
H = – 188.3 kJ / mole
(A) The value of Kp falls with rise in temperature
(B) The value of Kp falls with increase in pressure
(D) q p 
qv
2
13.
14.
15.
16.
17.
(C) Adding V 2O5 catalyst increases the equilibrium yield of sulphur trioxide
(D) The value KP = KC
Ionic product of water (Kw) increases when temperature increases from 0oC to 100oC
(A) 25 times
(B) 75 times
(C) 55 times
(D) 65 times
Which solution has the highest boiling point:
(A) 5.85% solution of sodium chloride
(B) 18.00% solution of glucose
(C) 6.00% solution of Urea
(D) All have the same boiling point
Which statement is not correct about galvanic cell?
(A) Anode is negatively charged
(B) Reduction occurs at anode
(C) Cathode is positively charged
(D) Reduction occurs at cathode
Oxidation state of chromium in K2CrO4 is:
(A) 5
(B) 6
(C) 3
(D) 7
The unit of rate constant is the same as that of the rate of reaction in:
(A) First order reaction
(B) Second order reaction
(C) Zero order reaction
(D) Third order reaction
1st Year Lahore Board 2013
Chemistry – Paper I
Time Allowed: 3. 10 Hours
(Essay Type)
Group – I
Max. Marks: 83
PART – I
2.
Write short answers to any EIGHT (8) questions:
(i)
16
Low of conservation of mass has to be obeyed during stoichiometric calculation, give
reason.
(ii)
One mg of K2CrO4 has thrice the number of ions than the number of formula units when
ionized in water, justify.
3.
(iii)
How many molecules of water are there is 10g of ice?
(iv)
Differentiate between adsorption chromatography and partition chromatograph.
(v)
Give the importance of sublimation.
(vi)
Explain Boyle’s law with the help of ICMT.
(vii)
SO2 is comparatively non ideal at 273 K hut behave ideally at 327oC .
(viii)
Give two applications of plasma.
(ix)
Ice occupies more space then water, give reason.
(x)
Water and ethanol can mix is all proportions, give reason.
(xi)
Ionic solids do not conduct electricity in solid state, give reason.
(xii)
Diamond is insulator and hard, give reason.
Write short answers to any EIGHT (8) questions:
16
(i)
State spin quantum number (s) briefly.
(ii)
What is Planck’s quantum theory?
(iii)
Write properties of positive rays.
(iv)
Why
(v)
Define ionization energy and write its variation in the periodic table.
(vi)
The pond angels of H2O and NH3 are not 109.5o like that of CH4. Although O-atom and N-
e
value for the cathode rays is just equal to that of electron?
m
atom are SP3 hybridized like C-in CH4. Give reason.
(vii)
The dipole moments of CO 2 and CS2 are zero but that of SO2 is 1.61D.
(viii)
What is the basic assumption of VSEPR theory, and discuss the shape of a molecule (BF 3)
containing three electron pairs?
4.
(ix)
Define the term state function, give two examples.
(x)
Explain the term enthalpy.
(xi)
State Le=Chatelier’s principle.
(xii)
What is buffer capacity?
Write short answers to any SIX (6) questions:
(i)
Give the twp applications of the solubility product.
(ii)
Depression in freezing point is a colligative property. Justify.
(iii)
What is meant by molality? Give its formula.
(iv)
Why NaCl and KNO2 are used to lower the melting points of ice?
(v)
Define electrochemical series.
(vi)
Lead accumulators is a chargeable battery, Justify.
(vii)
Calculate oxidation numbers of manganese in KMnO 4 and sulphur in SO42 .
12
(viii)
Define specific rate constant..
(ix)
What are enzymes? How they act as catalyst?
PART – II
NOTE: Attempt any THREE questions.
5.
(a)
(b)
6.
(a)
What is boiling point? What is the effect of external pressure on boiling point? Why the
temperature of a liquid remains constant at boiling point although heat is continuously
supplied?
4
An ideal gas is enclosed in a container having volume 500cm 3 at S.T.P. Its mass comes out
to be 0.72g. What is the molar mass of this gas?
4
(b)
Explain the m0lecular orbital structures of following molecules on the basis of the MOT:
(i)
N2 (Nitrogen)
(ii)
O2 (Oxygen)
4
State first law of thermodynamics. Prove that E = qv
4
7.
(a)
(b)
State Dalton’s law of partial pressure, also give its three applications.
Describe Millikan’s Oil Drop Method for the measurement of charge on electron.
8.
(a)
(b)
Describe the construction and the working of standard hydrogen electrode.
4
What is the percentage ionization of acetic acid in a solution in which 0.1 moles of it has
been dissolve d per dm3 of the solution?
4
9.
(a)
Give three statements of Raoult’s law and also mention how Raoult’s law helps in
determining the ideality of a solution.
4
What is Arrhenius equation? How it can be used to calculate activation energy of a
reaction?
4
(b)
4
4
PART – III
NOTE: Attempt any TWO questions.
(i)
(ii)
Write down standard solution, chemical equation with mole ratio, indicator with end point,
calculation for part A, B and C.
1, 1, 1, 1, 1
Write down material required, diagram and procedure for Part D and E.
1, 1, 3
A.
The given solution contains 5.6 g of alkali metal hydroxide ‘MOH’ dissolved per dm 3. Find out the
atomic mass of metal ‘M’ Volumetrically.
5
B.
Determine the % composition of 8 g mixture of KMnO 4 and K2SO4 per dm3 by volumetric method.
(Molecular Mass of Kmn4 = 1.58)
5
C.
24.8 of Na2S2O3.xH2O have been dissolved per dm3. Find out the value of ‘X’ by volumetric
method. (Molecular mass of Na2S2O3 = 158)
5
D.
them by using paper chromatographic method?
E.
5
How you could prepare the crystals of benzoic acid form water by using crystallization
method?
5