Class XI - Chem.

XI-A
HALF YEARLY ExAMINATION-2022-23

CHEMISTRY (043)
CLASS-XI
Time: 3 Hrs. Max. Marks: 70
General Instructions:
(1) Section A consists of 10
questions of 1 mark each.
(2) Section B short answer
type of 15 questions of 2 marks each.
(3) Section C short answer type
of 5 questions of3 marks each.
(4)
(4) Section D long answer type 3 questions of 5 marks each.
SECTION -A
Q.1. The Number of moles
present in 6g of carbon is:
(a) 2
(b) 0.5
(c) 5
(d) 1
Q.2. The significant figures in 3400 are
(a) 2
(b) 5
c) 6
(d) 4
Q.3. The atomic orbital is:
(a) The circular path of electron
(b) Elliptical shaped orbit.
(c)Three-dimensional field around nucleus
(d)The region in which there is
maximum probability of
Q.4. Which of the following is not finding an electron.
(a) n = 4, 1 = 3, m = 0
possible?
(6) n=
= 4, 1 =
2, m 1
(c) n 4 , 1= 4, m = 1
(d)n= 4, 1 = 0, m = 0
Q.5. The correct order for the size of I,
I, F is
(a)I>F>I (6) I> I>F
(c) F>I>I (d) I> I>I
Q.6. The correct order of electro
negativity is
(a) Cl>F>0> Br
(b) F>>0> Cl> Br
(c) F> Cl> Br >0
(d) O>F> CI> Br
Q.7. In structure of benzene
molecule the number of sigma and Pi bonds are
(a) 3 and 12
(b) 3a and 3T
(c) 6o and 6T (d) 12a and 12T
(1) P.T.O.
is
Q.8. The correct bond order in the following species
(a) (b) O <0; <0;

(d) o <0, <0;
(c) O <0 <0
easily between element with comparatively
Q.9. lonic bonds will be formed more
enthalpy
(a) low lonization enthalpy and high electron gain
enthalpy
(b) high lonization enthalpy and high electron gain
(c) low lonization enthalpy and low electron gain enthalpy
enthalpy and low
lonization electron gain enthalpy
(d) high
Q.10. Which one will have highest 2nd lonization enthalpy?
(a) ls 2s 2p 3s (b) 1s 2s 2p
(c) 1s 2s 2p (d) 1s 2s 2p 3s
SECTION-B
sodium sulphate.
Q.11. Calculate the mass percent of different elements present in
[Atomic mass: Na= 23u; S = 32u; O = 16u]
Q.12. Calculate the concentration of nitric acid in moles per litre in a sample which has
a density 1.41 g mL and mass percent of nitric acid in it is being 69%.
[Molar mass of nitric acid = 63g mol-]
Q.13. Yellow light emitted from a sodium lamp has a wavelength of 580nm. Calculate
the frequency and wave number of yellow light.
How many sub shells associated with =
4?
Q.14. (a) are n
(6) How many electron will be present in the sub shells having M, value of
for n = 4?
Q.15. State and explain the following:

(a) Pauli exclusion Principle
(b) Hund's rule of maximum multiplicity.

Q.16. The uncertainty in the position and velocity of a particle are 10-1m and
5.27x 1024 ms' respectively calculate the mass of particle.
Q.17.(a) Define electron gain enthalpy.
b) Explain why the electron gain enthalpy of fluorine is less negative than that
of chlorine
Q.18. Nitrogen has positive electron gain enthalpy whereas oxygen has negative.
However, Oxygen has lower ionization enthalpy than nitrogen. Explain why.
Q.19. Explain why PCI, is trigonal bipyramidal whereas IF, is square pyramidal. Also
draw their structures.
(2)
character
theory compare the bond enthalpy and magnetic

Q.20. Using molecular orbital
of O and 0
on bond order in N, and O,? Explain
Q.21. What is the effect of following
processes
+e
) N N
+e
ii) 0, 0
for the following:
Q.22. Give reasons
is linear.
carbon dioxide molecule
Water molecule has bent structure whereas
(a)
Ethyne molecule is linear.
(b) has highest
of elements decreases along
the period but Neon
Q.23. The atomic radius
element. Explain why.
size among third period
Q.24. Among the elements B, Al, C and Si
(a) Which has the first highest ionization enthalpy?

radius?
b)Which has the largest atomic
both are pyramidal?
moment NF, though
than
Q.25. Why NH, has high dipole
SECTIONC
with the following quantum
Q.26. (a) Usings, p, d, f notation, describe the orbital
number values:
i) n =4, (i) n 3, 1 =2
l= 0
=
electron moving with 1% speed of

Calculate de Broglee wavelength of an
(b)
(b)
light.
reasons for the difference
chemical behaviour of the first member
Q.27. Explain the
to that of the subsequent
of a group of elements in the s-and p-blocks compared
members in the same group.
OR
below:
The first ionization enthalpy values of
13 elements are given
B Al Ga In TI
801 577 579 558 589
How would you explain this general trend?
deviation from the
/mL. Calculate the molarity
Q.28. The density ofthe 3 molal solution of NaOH is 1.110g
of the solution.
orbital
combination of atomic
.29. Explain the important conditions required for linear
to form molecular orbitals.
does not exIst.
.30. (a) Using molecular orbital theory, explain why the Be, molecule
(b) Why axial bonds in PCI, longer than equatorial bonds? Explain.
(c) Define hydrogen bonding.
P.T.O.
(3)
SECTION-D
molecule using VSEPR theory:
Q.31. Discuss the shape of the following
BeCl, BCI,, SiCl, AsF,, H,S.
Define all the four Quantum Numbers associated
with an atom and give
Q.32. (a)
suitable explanation for each.
(b) Draw the boundary surface diagram of three 2p orbitals.

Q.33. Assertion: Generally, ionization enthalpy increases from left to right in period.
Reason: When successive electrons are added to the orbitals in same principal
quantum level, the shielding effect of inner core of electrons does not increases
as much.
(a) Define the lonization enthalpy

(b) Explainthe trend of lonization
enthalpy along the period and group in
modern periodic table.

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XI-A

HALF YEARLY ExAMINATION-2022-23

(a) (b) O <0; <0;

Q.15. State and explain the following:

(b) Hund's rule of maximum multiplicity.

theory compare the bond enthalpy and magnetic

Q.24. Among the elements B, Al, C and Si

(a) Which has the first highest ionization enthalpy?

electron moving with 1% speed of

(b) Draw the boundary surface diagram of three 2p orbitals.

(a) Define the lonization enthalpy

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