Class 11 Question Paper 2022-23 Chemistry (Half Yearly)

HALF YEARLY EXAMINATION

Question Paper
2022-23

NCERT BASED SYLLABUS
FOR CBSE AND STATE BOARD
FOLLOWING NCERT

QUESTION PAPER
PT-
PT-2/HALF
2/HALF YEARLY EXAMINATION, 2022
2022-
22-23
CHEMISTRY
Time – 3 hrs. Class – XI M.M. : 70
Date – 12.09.2022 (Monday)
Name of the student _________________________________________________ Section _____

GENERAL INSTRUCTIONS:
• All questions are compulsory.
• Question nos. 1 to 21 are MCQs with one
correct option and carrying 1 mark each.
• Question nos. 22 to 24 are objective/short
answer type questions.
• Question nos. 25 to 28 are of 2 marks each.
• Question nos. 29 to 32 is of 3 marks each.
• Question nos. 33 to 35 is of 5 marks each.
SECTION - A
Q. 1 to 21 is of 1 mark each.
Q1. The electron present in 5th orbit in excited hydrogen atoms returned back to ground
state. The no. of lines which appear in Lyman series of hydrogen spectrum
1) 5 2) 10 3) 4 4) 6
Q2. The bond lengths and bond angles in the molecules of methane, ammonia, and water are
given below: This variation in bond angle is a result of
(i) the increasing repulsion between H atoms as the bond length decreases
(ii) the number of nonbonding electron pairs in the molecule
(iii) a nonbonding electron pair having a greater repulsive force than a bonding electron
pair
A. (i), (ii), and (iii) are correct B. (i) and (ii) are correct
C. (ii) and (iii) are correct D. only (i) is correct
Q3. Molecular shapes of SF4, CF4 and XeF4 are
(a) the same with 1, 1 and 1 lone pair of electrons respectively on the central atom
(b) the same with 1, 0 and 2 lone pairs of electrons respectively on the central atom
(c) different with 0, 1 and 2 lone pairs of .electrons respectively on the central atom
(d) different with 2, 0 and 1 lone pairs of electrons respectively on the central atom

(e) different with 1, 0 and 2 lone pairs of electrons respectively on the central atom
Q4. Which of the following is a correct set?
(a) NH3 sp3 pyramidal (b) H2O sp2 linear
(c) NH 4+ dsp2 square planar (d) CH4 dsp2 tetrahedral

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Q5. The strength of sigma bonds formed by axial overlap of s or p - orbitals of 2nd shell of
participating atoms decreases as.
(a) s-s > p-s > p-p (b) s-s > p-p > s-p (c) p-s > s-s > p-p (d) p-p > s-p > s-s
Q6. Which of the following statements is not true about covalent compounds?
(a) They may. exhibit space isomerism (b) They have low melting and boiling points
(c) They show ionic reactions (d) They show molecular reactions
Q7. Which one of the following ions is paramagnetic?
(a) Ag+ ( Z= 47 ) (b) Fe2+ (c) K + (d) Mg2+
Q8. Which of the following statements is incorrect?
(a) Among all the elements, fluorine has the highest electron gain enthalpy
(b) Among all the elements, helium has the highest ionisation enthalpy
(c) Elements of groups 1,2, 13, 14, 15, 16 and 17 are called representative elements
(d) All the d-block elements are metallic in nature
Q9. The significant figures in 0.00051 are ________
(a) 5 (b) 3 (c) 2 (d) 6
Q10. Select the correct option for increasing order of number of atoms.
(I) 2 g of hydrogen (II) 16 g of sulphur ( S = 32 )
(III) 4 g of oxygen (IV) 31 g of phosphorus (P= 31)
(a) II > III > IV > I (b) IV > II > III > I (c) I > IV > II > III (d) I = IV > II > III
Q11. Select the correct statement(s) for the following reaction:
2 A(s) + B(g)----- 3 C (g) + 4 D (l)
(a) 2 moles of A always produce 3 moles of C and 4 moles of D
(b) 22.4 L of B (g) produces 3 moles of C at 1 atm and 273 K in excess of A.
(c) B will always remain in excess because volume of gas is very high than solid.
(d) Moles of D produced is always less than C because volume of liquid is less than gas.
Q12. The mole fraction of solute in one molal aqueous solution is
(a) 0.009 (b) 0.018 (c) 0.027 (d) 0
Q13. The ratio of masses of Dioxygen and Dinitrogen in a particular gaseous mixture is 1 : 4.
The ratio of number of their molecule is
(a) 1 : 4 (b) 1 : 8 (c) 7 : 32 (d) 3 : 16
Q14. For the reaction, 7 A + 13 B + 15 C ----17 P if 15 moles of A, 26 moles of B and 30.5
moles of C are taken initially then limiting reactant is

(a) A (b) B (c) C (d) None of these
Q15. The explanation for the presence of three unpaired electrons in the nitrogen atom can be
given by
(a) Pauli’s exclusions principle (b) Hund’s rule
(c) Aufbau’s principle (d) Uncertainty principle

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Q16. The shortest wavelength of He+ in Balmer series is x. Then longest wavelength in the
Paschene series of Li+2 is
(a) 36x/ 5 (b) 16x/ 7 (c) 9 x/5 (d) 5 x/9
Q17. The ratio of the radii of the first three Bohr orbits is
(a) 1 : 0.5 : 0.33 (b) 1 : 2 : 3 (c) 1 : 4 : 9 (d) 1 : 8 : 27
Q18. The decreasing order of energy of the 3d, 4s, 3p, 3s orbitals is
(a) 3d > 3s > 4s > 3p (b) 3s > 4s > 3p > 3d
(c) 3d > 4s > 3p > 3s (d) 4s > 3d > 3s > 3p

Q19. The value l and m for the last electron in the Cl − ion are
(a) 1 and 2 (b) 2 and +1 (c) 3 and –1 (d) 1 and –1

Q20. The ratio of the energies of photons of 2000 A0 to that of 4000 A0 is
(a) 2 (b) 4 (c) 1/ 2 (d) 1/ 4
Q21. Ionisation energy of nitrogen is more than oxygen because:
(a) nucleus has more attraction for electrons (b) half-filled p-orbitals are more stable
(c) nitrogen atom is small (d) more penetration effect
Q.22 Answer the following. (1x5=5)
a) Define molality?
b) 1 femtometer is equals ________m.
c) State the law of multiple proportions.
d) Round off 3.45895 upto two significant figures.
e) Find the number of radial and angular nodes present in 4p orbital.
Q.23 Match the following. (1x5=5)
A B
i. Uncertainity principle a) Hund
ii. Exclusion principle b) Heisenberg
iii. Vanderwaals radius c) Pauli
iv. Acidic oxide d) Hydrogen

v. Amphoteric oxide e) CO
f) CO2
g) Al2O3
h) Argon
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Q.24 Answer the following. (1x4=4)
a) Write the IUPAC name of element with atomic number 107.
b) How many sigma and π–bonds are there in

c) The shape of PCl5 molecule is ___________.
d) The dipole moment of CO2 molecule is ____________

Section – B
Q.25 to 28 is of 2 marks each.
Q.25 40 kg of N2 and 15 kg of H2 are mixed to produce NH3(g). Calculate the mass of NH3 gas
formed.
Q.26 Write two differences between sigma and pie bond.
Q.27 Write the electronic configuration and find the group and period of element with atomic
number 80.
Q.28 Write the electronic configuration of -
a) Fe2+ (Z=26) b) Cr (Z=24)

Section – C
Q.29 to 32 is of 3 marks each.
Q.29 A solution is 25% water, 25% ethanol (C2H5OH) and 50% acetic acid (CH3COOH).
Calculate the mole fraction of each component.
Q.30 How much energy is required to ionise a H-atom if the electron occupies n=5 orbit.
Compare your answer with the ionisation enthalpy of H-atom. (Energy required to
remove the electron from n=1 orbit)
Q.31 What is ionisation enthalpy? How it varies across the 2nd period in periodic table. Justify
your answer.
Q.32 What is electron gain enthalpy? How it varies down the group in group 17. Give reason for
your answer.

Section – D
Q. 33 to 35 is of 5 marks each.
Q.33 Answer the following.
a) Between NH3 and NF3 which has higher dipole moment and why ? (2)
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b) Show the hybridisation of H2O molecule indicating bond angle and shape. (2)

c) Draw the Lewis dot structure of O3 molecule. (1)

OR

a) Define the term – (i) Bond order (ii) Bond enthalpy.

b) Show the hybridisation in CO2 molecule indicating bond angle and shape.

c) Between LiCl and LiI which is more covalent and why.

Q.34 a) Electrons are emitted with zero velocity from a metal surface when it is exposed to
radiation of wavelength 7000 Ao. Calculate threshold frequency (V0) and work function
(W0) of the metal. (2)

b) Write short notes on the following : (3)

i) Absorption spectrum ii) Azimuthal quantum number iii) Balmer series

OR

a) What is the energy in joules required to shift the electron of the H-atom from 1st Bohr
orbit to 6th Bohr orbit and what is the wave length of light emitted when electron
returns to ground state ? The ground state electron energy is –2.18×10-11 ergs. (2)

b) Write any two drawback of Bohr’s atomic model. (1)

c) Draw the shape of following orbitals - (i) dxy (ii) Pz (1)

d) State Aufbau’s principle. (1)

Q.35 a) A compound contains C, H and O only. A 4.24 mg of sample of the compound
completely burnt to produce 8.45 mg of CO2 and 3.46 mg of H2O. If the molecular mass
of the compound is 88 u then determine its molecular formula ? (3)

b) What volume of 10 M HCl and 4 M Hcl should be mixed to get 1 L of 6 M HCl solution? (2)

OR

a) A solution of sulphuric acid is 65% by mass. Its density is 1.76 gm/cm3. Find out the
molarity and molality of the solution. (The MW of H2SO4 = 98)

b) Pressure is defined as force per unit area of the surface. the SI unit of pressure is
pascal is shown below

1 pa = 1 N m-2

If mass of air at sea level is 1034 gm/cm2. Calculate the pressure in pascal.

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