St.

Mary’s Higher Secondary School, Mhow

HALF YEARLY
CLASS – 11TH SESSION – 2024-25
EXAMINATION 2024
SUBJECT – CHEMISTRY
DURATION : 3 hr. M.M.: 70
CHEMISTRY

General instructions

1. There are 33 questions in this question paper with internal choice.

2. SECTION A consists of 16 multiple choice questions carrying 1 mark each.

3. SECTION B consists of 5 very short answer questions canying 2 marks each.

4. SECTION C consists of 7 short answer questions carrying 3 marks each

5. SECTION D consists of 2 case-based questions carrying 4 marks each.

6. SECTION E consists of 3 long answer questions carrying 5 marks each.

7. All questions are compulsory.

8. The use of log tables and calculators is not allowed

SECTION A

The following questions are multiple choice questions with one correct answer. Each
question carries one mark.

1. Absorption spectrum, seen as dark lines in an otherwise continuous spectrum, for the
given material results from [1] the material's (atom or molecules):

a) Absorbing selected wavelengths and returning to normal ground state

b) Absorbing selected wavelengths from an input of continuous spectrum

c) Absorbing all wavelengths and returning to normal ground state

d) Absorbing all wavelengths from an input of continuous spectrum

2. The orbital with n-3 and 1-2 is

a) 3p b) 3d c) 35 d) 3f

3. Which of the following statements is not correct for a nucleophile?

 a) Nucleophiles are not electron seeking.

b) Ammonia is a nucleophile.

c) Nucleophiles attack low electron density sites,

d) Nucleophile is a Lewis

4. The correct order of electronegativity of . Na, O and F is

a) Na >>0> O > F b) O > F > Na

c) O > Na > F d) F > O > Na

5. The number of atoms present in one mole of an element is equal to Avogadro number.
Which of the following elemetit contains the greatest number of atoms?

a) 12g He b) 46g Na c) 0.40g Ca d) 4u He

6. Photoelectric effect established thar light can also

a) Behave like rays

b) Behave like magnetic fields

c) Behave like waves

d) Behave like particles

7. Energy of an electron in stationary state is given by the formula

Enth=RH(1-1/n2)

where n 1,2,3. In this equation, Rer is called

a) Rydberg's constant

b) Planck's constant

c) Proportionality constant

d) Avagadro's Number

8. The IUPAC name of the following compund is CH₂CH CHO

a) 3-methyl isobutylaklehyde b) 2-metylbutanal

c) 2-ethylpropanal d) butan-2- aldehyde

9. D-Block Elements are characterized by the

a) Inner d orbitals are not filled.

 b) Absence of d orbital elects Electrilling of outer d or bicombining filling of merd
orbitals by electrons

10.Neutron was discovered by… … …

(a) J.J Thomson b) Chadwick

(c) Rutherford d) Priestley

11.Principal, Azimuthal and magnetic quantum numbers are respectively related to:

(a) Size, shape and orientation

(b) Shape, size and orientation

(c) Size, orientation and shape

(d) None of the above

12.Which of the following is not permissible?

(a) n = 4 I = 3 m = 0 (b) n = 4 I = 2 m = 1

(c) n = 4 I = 4 m = 1 (d) n = 4 I = 0 m = 0

Assertion-Reason:

a) Both A and R is true and R is the correct explanation of A

b) Both A and Rare true but R is not the conect explanation of A

c) A is false hat R is true..

d) A is true and R is false

13.Assertion (A): Electronic configuration of an element is 1s2 2s

Reason (R): In 2s, 2 signifies the maximum capacity of s-subshell

14.Assertion (A): Law of conservation of mass hold good for nuclear reaction,

Reason (R): Law states that mass can be neither created nor destroyed in a chemical
reaction.

15.Assertion-Among the isomeric paintings 22 dimethylpropane has lowest boiling point

Reason -branching does not affect the boiling point

16.Assertion: In a triad, the three elements present have same gaps of atomic masses.

Reason: Elements in a triad have similar properties.

 SECTION B

This section contains 5 Short answer questions with internal choice in one question
each question carries 2 marks

17.Write the electronic configuration of Cu atomic no. 29 Ca atomic no 20

18.Write the hybridisation and its shapeof the give compounds (any 2) .PCl6, XeF2 Or
CH4

19.Draw the Lewis Dot Structure of NaCl and NO2-

20.Find the mass percent of each element in Na2SO4.

21.Chlorophyll present in green leaves of plants absorbs light at 4.620 x 1014 Hz. Calculate
the wavelength of radiation in nanometer. Which part of the electromagnetic spectrum
does it belong to?
OR

Table-tennis ball has a mass of 10 g and a speed of 90 m/s. If speed can be measured with
an accuracy of 4% what will be the uncertainty in speed and position?

SECTION C

This section carries 7 short answer questions each question carries 3 marks

22.What will be the molarity of a solution, which contains 5.85 g of NaCl(s) per 500 mL?

23.Problem 2: A sulphide of iron was formed by combining 1.926g of sulfur(s) with 2.233g
of iron (Fe). What is the compound's empirical formula?

24.Write the IUPAC names of the following,:

a) CH3 (CH2) 2C(CH3)2 CH2CHCl
b) CH3 CH(OH) CH2 COOH
c) C6H5 CH3

25.Which of the following species, do not show a disproportionation reaction and why?
Mathematical,ClO3 ,ClO2 ,CIO, and CIO4, Also, write the reaction for each of the species
that disproportionate.
26.The Balmer series in the hydrogen spectrum corresponds to the transition from n1 =
 2,and n2=3,4,…This series lies in the visible region. Calculate the wave number of line
associated with the transition in Balmer series when the electron moves to n= 4 orbit
(K=109677 cm)

27.What are the various factors due to which the ionization enthalpy of the main group
elements tends to decrease 131 down the group?

28.How many significant figures are present in

a) 8.256 b) 100 c) 4.02x102 d) 32.6

SECTION D

Read the following passage and answer the following questions. Each question
carries of 4 marks.

29.The attractive force which holds the twoatoms together is called chemical bond.
Covalent bond is formed by equal sharing of electrons. Coordinate bond is formed by
unequal sharing of electrons. Ionic bond is formed by transfer of electrons from one
atom to another. Octet rule, although very useful but it is not universally applicable.
According to valence bond theory, covalent bond is formed by overlapping of half filled
atomic orbitals resulting in lowering of energy and more stability. Bond order is the
number of bonds between atoms in a molecule. Higher the bond order, more will be
stability and bond dissociation enthalpy but smaller bond length. Polarity of covalent
bond depends upon difference in electronegativity. Covalent character of bond depends
upon polarising power, smaller cation and bigger anions have higher polarising power.
VSEPR theory helps to predict shapes of molecules.

(a) Write the, electron dot structure of N2O.

(b) What are ions present in Csl3?

(c) Out of CN, CN, NO, which has highest bond order?

(d) What is correct order of repulsion bp - bp, IpIp and Ip - bp?

(e) Draw the structure of XeOF4 on the basis of VSEPR theory.

(f) Which out of B2, CO, O2 and NO are paramagnetic and why?
30.Red ox reactions are reactions in which oxidation and reduction takes place
simultaneously. Oxidation number are assigned in accordance with the set of rules.
Oxidation number and ion electron methods both are used in balancing ionic equations.
Redox reactions are classified as combination, decomposition, displacement and
disproportionation reactions. The concept of redox couple and electrode processes is
basis of electrolysis and electrochemical cells.

(a) What are oxidation numbers of each individual Br in Br3 O8?

(b) If electrolysis of CuSO4 solution is carried out using Cu electrodes, what will be

reaction taking place at anode.

(c) What is oxidation number of Cr in CrO5?

(d) Give one example of disproportionation reaction.

SECTION E

The following questions are long answer type questions each question carry 5 marks

31.Write a short note on any 2

1) Reduced pressure distillation,

2) Column distillation
3) Chromatography
4) Fractional distillation.

32.What is hyper conjugation Explain

OR

Explain resonance with proper example.

33.Explain energy level diagram of O2 (g) or N2(g)

OR

Write a brief note on

a) photo electric effect b) Hybridisation

OR

Explain the VSEPR theory in detail through an example.