ANNUAL EXAMINATION, FEBRUARY 2023

SUBJECT: CHEMISTRY (043)

Grade: 11 Time: 3 Hrs.

Date: 17/02/2023 Max. Marks: 70

General Instructions:
Read the following instructions carefully.
a) There are 35 questions in this question paper with internal choice.
b) SECTION A consists of 18 multiple-choice questions carrying 1 mark each.
c) SECTION B consists of 7 very short answer questions carrying 2 marks each.
d) SECTION C consists of 5 short answer questions carrying 3 marks each.
e) SECTION D consists of 2 case- based questions carrying 4 marks each.
f) SECTION E consists of 3 long answer questions carrying 5 marks each.
g) All questions are compulsory.
h) Use of log tables and calculators is not allowed.
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SECTION A
The following questions are multiple-choice questions with one correct answer. Each question
carries 1 mark. There is no internal choice in this section.
1. Calculate the standard molar volume of oxygen gas. The density of oxygen gas at NTP is 1.429g/L.
a) 11.19 Litres
b) 22.39 Litres
c) 24 Litres
d) 24.4 Litres
2. Out of the following pairs of electrons, identify the pairs of electrons present in degenerate orbitals.
a) (i) n = 3, l = 2, ml = - 2, ms = - ½ (ii) n = 3, l = 2, ml = -1, ms = - ½
b) (i) n = 2, l =2, ml =0, ms = + ½ (ii) n = 2, l = 2, ml =1, ms = + ½
c) (i) n = 4, l =1, ml =-1, ms = + ½ (ii) n = 3, l = 1, ml =1, ms = + ½
d) (i) n = 3, l = 1, ml = + 2, ms = - ½ (ii) n = 3, l = 2, ml = 0, ms = + ½

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3. If the concentration of glucose in blood is 0.9 g L–1, what will be the molarity of glucose in blood?
a) 5 M
b) 50 M
c) 0.005 M
d) 0.5 M
4. The uncertainties in the velocities of two particles A and B are 0.05 and 0.02 m.sec−1 respectively.
The mass of B is five times to that of mass A. What is the ratio of uncertainties [ΔxB/ΔxA] in their
positions?
a) 2
b) 0.25
c) 4
d) 2.5
5. Consider the following statements:
I. The radius of a cation is larger than that of parent atom.
II. The I.E. increases from left to right in a period generally.
III. The electronegativity of an element is the tendency of an isolated atom to attract an
electron.
The correct statement is (are):
a) III alone
b) II alone
c) I and II
d) II and III

6. The types of hybrid orbitals of nitrogen in NO3-, NO2+ and NH4+ respectively are expected to be:
a) sp, sp and sp3
b) sp, sp2 and sp3
c) sp2, sp and sp3
d) sp2, sp3 and sp
7. Oxidation states of X, Y, Z are +2, +5 and -2 respectively. Formula of the compound formed by
these will be:
a) X2YZ6
b) XY2Z6
c) X2Y5Z2
d) X3YZ4

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8. In case of peroxides and super oxides, oxidation number of oxygen atoms respectively are:
a) −1/2 and −1
b) −1 and −2
c) − 1 and +1/ 2
d) −1 and −1/2
9. Which law of thermodynamics is similar to the law of conservation of energy?
a) Zeroth law of thermodynamics
b) First law of thermodynamics
c) Second law of thermodynamics
d) Third law of thermodynamics

10.

Select the correct statement for the above figure.

a) It is the process in which there is the transfer of heat between the system and
surroundings.
b) Wall separating the system and the surrounding is called isolated wall.
c) It is the process which does not permit the transfer of heat through the boundary called
the adiabatic wall.
d) It is the process in which there is the transfer of heat through the boundary called the
adiabatic process.
11. Consider the following reversible chemical reactions,

The relation between K1 and K2 is:

-
a) K2 = K1 3

b) K2 K1 = 3

c) K2 = K13
d) K2 K1 = 1/3

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12. The IUPAC name of the given compound is:

a) 3-Methylcyclobut-1-en-2-ol
b) 4-Methylcyclobut-2-en-1-ol
c) 4-Methylcyclobut-1-en-3-ol
d) 2-Methyl cyclobut-3-en-1-ol
13. Which of the following compounds will exhibit geometrical isomerism?
a) CH2 = C(Br)I
b) CH3CH = C(Br)I
c) (CH3)2C = C(Br)I
d) CH3CH = CCl2
14. Conjugate base for Bronsted acids H2O and HF is:
a) H3O+ and H2F+, respectively
b) OH– and H2F+, respectively
c) H3O+ and F–, respectively
d) OH– and F–, respectively.
15. Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion(A): Electron gain enthalpy becomes more negative as we go down a group.
Reason(R): Size of the atom increases on going down the group and the added electron
would be farther from the nucleus.
Select the most appropriate answer from the options given below:
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
16. Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion(A): Bond energy has order like C − C < C = C < C ≡ C.
Reason(R): Bond energy increases with increase in bond length.
Select the most appropriate answer from the options given below:
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.

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 c) A is true but R is false.
d) A is false but R is true.
17. Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion(A): A covalent bond may be cleaved by either heterolytic or homolytic cleavage.

Reason(R): Heterolytic cleavage of CH3Br will give CH3+ and Br- ions.
Select the most appropriate answer from the options given below:
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
18. Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion(A): Nitration of benzene with HNO3 requires the use of conc: H2SO4.
Reason(R): The mixture of concentrated sulphuric acid and concentrated nitric acid produces
the electrophile, NO2+.
Select the most appropriate answer from the options given below:
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
SECTION B
This section contains 7 questions with internal choice in two questions. The following questions
are very short answer type and carry 2 marks each.
19. A certain compound contains only Carbon and Oxygen. Analysis show that there is 36% carbon
and the rest is oxygen in the compound. If its molecular mass is 400, then what is the molecular
formula of the compound? [2]
20. a) Why don't we observe the wave properties of large objects such as a cricket ball or an
aeroplane? [1]
b) If the largest value of ml for an electron is +3, in what type of subshell may the electron be
present? [1]
21. Permanganate ion, MnO4− oxidizes I − ion to I2 and gives manganese (IV) oxide MnO2 in basic
medium. Write the skeleton equation for the process and balance them by ion electron method. [2]
OR
Balance the redox equation by ion electron method.
MnO4− + C2O42− + H+ Mn2+ + CO2 + H2O

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22. Study the graph and answer the following question:

What conclusion can you derive from the graph regarding the first ionization enthalpies of
given group elements? Identify the groups and justify your answer. [2]
23. Nitrogen and hydrogen react to form ammonia as per the reaction,
1/2 N2(g) + 3/2 H2 (g) NH3 (g) + 46 kJ/mol
a) When the mixture of the three gases is in equilibrium, predict whether the amount of ammonia
increases or decreases if:
i) the pressure on the system is increased
ii) the temperature of the system is raised. [1]
b) What will be the effect of (i) decrease of temperature (ii) increase of volume of the reaction vessel,
on equilibrium constant of above reaction. [1]
24. How would you obtain butane by:
i) Wurtz reaction ii) Kolbe’s electrolysis [2]
OR
An alkene ‘A’ on ozonolysis gives a mixture of acetaldehyde and acetone. Write the reaction and
IUPAC name of ‘A’.
25. Predict the major product in the following reactions: [2]
a) b) b)

SECTION C
This section contains 5 questions with internal choice in two questions. The following questions are short
answer type and carry 3 marks each.
26. a) 10ml of HCl solution produced 0.1435g of AgCl when treated with silver nitrate solution. What is the
molarity of HCl solution [At. Mass of Ag = 108u, N = 14u, Cl = 36.5u and O = 16u]. The chemical
equation of the reaction is: [2]

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 HCl + AgNO3 AgCl + HNO3
b) Calculate the mass of one u (unified mass) in kilogram? [1]
27. a) Out of 4f and 6s sub-shells which has higher energy and why? [1+2]
b) "All atoms having even number of electrons always contain paired electrons"- is the statement true?
If so, then by what principle or rule can the above statement be explained? State the above principle.
OR
a) Point out the rule which has been disobeyed while writing these configurations.
B: Is2 2s2 3s1 C: 1s2 2s2 2px2
b) Energy of an electron in Hydrogen atom is given by expression,
1.312 x106
En = − J/mol.
𝑛2
Calculate the amount energy required to promote electron from the first energy level to third
energy level.
28. a) A student reported the radii of Cu, Cu+ and Cu2+ as 96pm, 122pm and 72pm respectively.
Do you agree with the reported values? Justify the answer.
b) What is the electronic configuration of Cu2+? How many unpaired electrons are present in it?
c) In what group of the periodic table is each of the following elements found? [1+1+1]
i) [Xe] 4f14 ,5d4, 6s2 ii) [Ar] 3d10, 4s2, 4p4
29. a) Why is that in SF4 molecule, the lone pair of electrons occupy equatorial position in
preference to axial position? What is the shape of the molecule? [1]
b) Sketch the bond moments in (i)SO2 and (ii) Cis-C2H2Cl2. [1]
c) Give two canonical structures of nitrite ion which satisfy octet rule? [1]
30. a) Write the IUPAC names of the following compounds:
i) ii) HC ≡ C – CH = CH – CH = CH [2]

b) Write the structural formula of 2-phenylprop-2-enal. [1]

OR
a) Draw the bond line structure of 5-bromohept-2-enoicacid.
b) Give the IUPAC name of the following compounds:
(i) Oxalic acid (ii) Isopropyl alcohol.
SECTION D
The following questions are case-based questions. Each question has an internal choice and
carries 4 (1+1+2) marks each. Read the passage carefully and answer the questions that follow.
31. Chemical energy stored by molecules can be released as heat during chemical reactions when a
fuel like methane, cooking gas or coal burns in air. Thermodynamics deals with energy changes
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 in chemical or physical processes and enables us to study these changes quantitatively and to
make useful predictions. For these purposes, we divide the universe into the system and the
surroundings. Chemical or physical processes lead to evolution or absorption of heat (q), part of
which may be converted into work (w). These quantities are related through the first law of
thermodynamics. The heat absorbed at constant volume is equal to change in the internal energy
i.e., ΔU = qV. But most of chemical reactions are carried out not at constant volume, but in flasks
or test tubes under constant atmospheric pressure is equal to change in the enthalpy, ΔH = qp,
heat absorbed by the system at constant pressure. There are varieties of enthalpy changes.
Enthalpy of formation, combustion and other enthalpy changes can be calculated using Hess’s
law.
Answer the following questions:
a) Two litres of an ideal gas at a pressure of 10 atm expands until its total volume is 10 litres.
How much work is done when gas expands isothermally into vacuum? [1]
b) Predict the entropy change involved in the following process:
i) 2NaHCO3(s) Na2CO3(s) + CO2 + H2O [1]
ii) H2 (g) 2H (g)
c) Calculate the heat of formation of glucose from the following data:
(i) C(s) + O2(g) → CO2(g); ΔH= −395.0kJ
(ii) H2(g) + 12O2(g) → H2O(l); ΔH= −269.4kJ [2]
(iii) C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(l); ΔH= −2900kJ.
OR
c) Calculate the entropy change when 40g of liquid water evaporates at 373 K
(ΔVapH = 40.63 kJ/mol).
32. Reactants and products coexist at equilibrium, so that the conversion of reactant to products
is always less than 100%. Equilibrium reaction may involve the decomposition of a covalent
(nonpolar) reactant or ionization of ionic compound into their ions in polar solvents. Ostwald
dilution law is the application of the law of mass action to the weak electrolytes in solution.
A binary electrolyte AB which dissociates into A+ and B– ions.

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Answer the following questions:
a) Write the Ksp expressions for calcium phosphate and Ag2CrO4. [1]
b) What is Common ion effect? [1]
c) Calculate the pH of a 0.001 M solution of Ba (OH)2 assuming it to be completely ionised.
(log 1 = 0, log 2 = 0.3010, log 3 = 0.477, log 4 = 0.6020, log 5 = 0.699)
OR [2]
c) How many grams of NaOH must be dissolved in one litre of the solution to give it a pH
value of 12? (antilog of x = 10x)
SECTION E
The following questions are long answer type and carry 5 marks each. Two questions have an
internal choice.
33. a) Compare the relative stability of the following species and indicate their magnetic properties:
O2+ and O22−. [21/2]
b) What is the full form of LCAO? Give two differences between bonding and antibonding molecular
orbitals. [11/2]
c) Sucrose is a covalent compound but it is quite soluble in water. Why? [1]
34. a) i) Which is more basic CH2 = CH − or CH ≡ C −. Explain. [2]
ii) Electromeric effect is a temporary effect. Why?
+
b) Draw the resonance structures of C6H5NH3. [2]
c) Draw the structure and write the IUPAC name of the lowest molecular weight alkane that
contains a quaternary carbon. [1]
OR
a) What are the hybridization states of each carbon atom in the following compounds? [2]
i) CH2 = C = CH - CH3 ii) CH2 = CHCONH2
b) Identify and define the type of isomerism involved in C2H5CN and C2H5NC. [1]
c) Which of the following compounds will not exist as resonance hybrid? Give reason for your answer.
i) CH3OH ii) R-CONH2 iii) CH3CH = CHCH2NH2 [2]
35. a) How will you distinguish the following pair of organic compounds by giving chemical tests?
i) Propane and propene.
ii) Ethane and ethyne. [2]
b) Identify ‘A’

[1]

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c) How will you convert:
i) Acetylene to acetophenone.
ii) 1,2-dichloroethane in to ethyne. [2]
OR
a) An alkyl halide (X) of formula C6H13Cl on treatment with alcoholic KOH gives two isomeric
alkenes Y and Z (C6H12). Both alkenes on hydrogenation give 2,3-dimethylbutane. Predict the
structure of X, Y and Z. [3]
b) Complete the following:
i)
[2]

ii)

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