LAHORE BOARD
Chemistry (New Scheme)
(Inter Part-I Class 11th)
Session (2019)
Time: 20 minutes
Marks: 17
Objective Section
Note: You have choices for each objective-type question as A, B, C, and D. The choice you think is correct, fill that circle in front of the question number with a marker or pen. Cutting or filling two or more circles will result in zero marks for that question.
Q.1: Answer all the following Multiple Choice Questions.
- The largest number of molecules is present in:
- (a) 5.4 g of Na
- (b) 2.8 g of CO
- (c) 4.8 g of C2H5OH
- (d) 3.6 g of H2O
- 1.00 mole of SO2 contains:
- (a) 6.02 x 10^23 atoms of oxygen
- (b) 3.01 x 10^23 molecules of SO2
- (c) 6.02 x 10^23 molecules of SO2
- (d) 3.01 x 10^23 atoms of sulfur
- Solvent extraction is a separation technique used for the product, which is:
- (a) Non-volatile; thermally unstable
- (b) Volatile; thermally stable
- (c) Non-volatile; thermally stable
- (d) Volatile; thermally unstable
- The deviation of a gas from ideal behavior is maximum at:
- (a) -10°C and 5 atm
- (b) -10°C and 2 atm
- (c) 100°C and 2 atm
- (d) 0°C and 2 atm
- The order of effusion of NH3, SO2, Cl2, and CO2 gases is:
- (a) NH3 > SO2 > Cl2 > CO2
- (b) NH3 > CO2 > SO2 > Cl2
- (c) Cl2 > SO2 > CO2 > NH3
- (d) NH3 > CO2 > Cl2 > SO2
- The density of ice is minimum at 4°C due to:
- (a) Empty spaces in the structure of ice
- (b) Tetrahedral shape of ice crystals
- (c) Large bond lengths
- (d) Large bond angles
- The solid which has no definite crystalline shape is:
- (a) Amorphous solid
- (b) Quartz
- (c) Salt
- (d) Sugar
- Quantum numbers which represent 2p 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 in the discharge tube depends upon the nature of:
- (a) Anode
- (b) Cathode
- (c) Residual gas
- (d) Discharge tube
- The nature of bonds in the N2 molecule is:
- (a) One sigma; two pi bonds
- (b) Two sigma; two pi bonds
- (c) Two sigma; one pi bond
- (d) Three pi bonds
- For the HF molecule, the dipole moment is 1.90 D and the ionic moment is 4.4 D. The percentage ionic character of the HF molecule is:
- (a) 100
- (b) 80
- (c) 57
- (d) 43
- The amount of heat absorbed when one mole of gaseous atoms is formed from the element is called the enthalpy of:
- (a) Formation
- (b) Reaction
- (c) Combustion
- (d) Atomization
- For which of the following reactions, the unit of the equilibrium constant (Kc) is the reciprocal of molar concentration (M^-1)?
- (a) 3H2(g) + N2(g) ⇌ 2NH3(g)
- (b) 2NO2(g) ⇌ N2O4(g)
- (c) H2(g) + I2(g) ⇌ 2HI(g)
- (d) N2(g) + O2(g) ⇌ 2NO(g)
- 18 g of glucose dissolved in 90 g of water has a relative lowering of vapor pressure equal to:
- (a) 18/20
- (b) 1/5
- (c) 18/108
- (d) 90/108
- The salt dissolved in water forms a solution of pH greater than 7:
- (a) NaCl
- (b) Na2CO3
- (c) CuCO3
- (d) NH4Cl
- The oxidation state of oxygen in OF2 is:
- (a) +1
- (b) -1
- (c) 0
- (d) +2
- The unit of the rate constant is the same as that of the rate of the reaction having the order:
- (a) Zero
- (b) One
- (c) Two
- (d) Three
LAHORE BOARD
Chemistry (New Scheme)
(Inter Part-I Class 11th)
Session (2019)
Time: 2:40 Hours
Marks: 68
Subjective Section
Note: Section I is compulsory. Attempt any 3 questions from Section II.
Section-I
Q.2: Write short answers to any EIGHT parts.
(8 × 2 = 16)
- Define relative atomic mass. Give two examples.
- Calculate the percentage of nitrogen in NH₂CONH₂ (Atomic masses: C = 12, N = 14, O = 16, H = 1).
- Define gram formula, giving one example.
- Write two disadvantages of drying crystals in the folds of filter paper.
- Define distribution law in relation to solvent extraction.
- Derive Graham’s law of diffusion from the kinetic equation.
- Give two reasons for the deviation of real gases from ideal behavior.
- Write down two characteristics of plasma.
- Derive the SI units of van der Waal’s constant “a”.
- Sea water has 5.65 x 10³ g of dissolved oxygen in one kg of water. Calculate the concentration of oxygen in sea water in parts per million (ppm).
- Define molal boiling point constant, giving one example.
- Define solubility curve. Name its two types.
Q.3: Write short answers to any EIGHT parts.
(8 × 2 = 16)
- Why does ice occupy 9% more volume than liquid water?
- Why does evaporation cause cooling?
- Write two applications of liquid crystals.
- Why is the heat of sublimation of iodine higher than other halogens?
- What are the defects of Rutherford’s atomic model?
- State Moseley’s law and also give its importance.
- Why is the e/m value of cathode rays equal to that of an electron?
- State Hund’s rule.
- How does a buffer act?
- Give the optimum conditions to get maximum yield of NH₃.
- Justify that radioactive decay is always a first-order reaction.
- Describe autocatalysis with an example.
Q.4: Write short answers to any SIX parts.
(6 × 2 = 12)
- Why can’t the radius of an atom be determined precisely?
- Define ionization energy. Give its trend in the periods and groups of the periodic table.
- How does electronegativity change in a group?
- Define coordinate covalent bond, giving one example.
- Explain that the burning of a candle is a spontaneous process. Justify.
- Define state and state function.
- Write the reactions taking place at the anode and cathode in a silver oxide battery.
- How is aluminum anodized in an electrolytic cell?
- Calculate the oxidation number of Cr in Al₂CrO₄.
Section-II
Note: Attempt any THREE questions:
(3 × 8 = 24)
Q.5:
(a) Describe the combustion analysis method for determining the percentage composition of an organic compound.
(b) Define ionic solids. Give their three properties.
Q.6:
(a) One mole of methane gas is maintained at 300 K, and its volume is 250 cm³. Calculate the pressure exerted by the gas, assuming it behaves as an ideal gas.
(b) Write four defects of Bohr’s atomic model.
Q.7:
(a) Draw the molecular orbital diagram for the O₂ molecule.
(b) State Hess’s law of constant heat summation. Explain it with two examples.
Q.8:
(a) Ca(OH)₂ is a sparingly soluble compound. Its solubility product (Ksp) is 6.5 x 10⁻⁶. Calculate the solubility of Ca(OH)₂.
(b) How does the Arrhenius equation help us calculate the activation energy of a reaction?
Q.9:
(a) State the three statements of Raoult’s law.
(b) Describe the electrolysis of a concentrated solution of NaNO₃ in an aqueous solution.