Goa Board Class 11 Sample Paper Chemistry

Sample Paper
&
Question Paper Pattern
2022
2023

GOA BOARD

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION
CLASS: XI SUBJECT:CHEMISTRY
SCHEME OF EAMINATION AND MARKS DISTRIBUTION (2022-23)
QUARTERLY SUPPLEMENTARY
DURATION IN MINUTES 60 90
MAXIMUM MARKS 20 30
NUMBER OF QUESTIONS 11 20
KNOWLEDGE 30% ±5%
UNDERSTANDING 40%±5%
WEIGHTAGE
SKILL 10%+5%
TO
OBJECTIVE APPLICATION 20%±5%
EXAMINATIONS(QUARTERLY/ Ist First term Inovative IInd Second SUPPLEM
SUPPLEMENTARY Qtly Test Qtly term ENTARY#

SOME BASIC CONCEPTS OF
1 CHEMISTRY 6±1 5±1
2 STRUCTURE OF ATOM 8±1 7±1
CLASSIFICATION OF ELEMENTS
3 AND PERIODICITY IN PROPERTIES 6±1 5±1
CHEMICAL BONDING AND
WEIGHTAGE TO

4 MOLECULAR STRUCTURE 8±1
5 STATES OF MATTER 4±1
6 THERMODYNAMICS 04±1 03±1 03±1
7 EQUILIBRIUM 09±1 09±1
8 REDOX REACTIONS 06±1 05±1 05±1
9 HYDROGEN 3±1
10 s-BLOCK ELEMENTS 03±1 02±1 02±1
CONTENT

11 p-BLOCK ELEMENTS 04±1 04±1
ORGANIC CHEMISTRY-SOME BASIC
12 PRINCIPLES & TECHNIQUES 8±1
HYDROCARBONS(CLASSIFICATION
13 ALKANES AND ALKENES) 7±1
HYDROCARBONS,ALKYNES,AROM 7±1
13 ATIC AND TOXICITY & 7±1
CARCINOGENICITY
14 ENVIRONMENTAL CHEMISTRY May be used as one of the topic for innovatve test
TOTAL 20 40 20 20 30 30
NO OF MARKS
WEIGHTAGE TO TYPES OF QUESTIONS QUESTIONS
TYPE OF MULTIPLE CHOICE QUESTION (MCQ) --- 02 02
QUESTIONS 1MARK
FOR QUARTELY VERY SHORT ANSWER (VSA)-- 1MARK 02 02
EXAMINATIONS SHORT ANSWER I (SA I)--2MARKS 05 10
SHORT ANSWER I (SA II)-- 3MARKS 02* 06
*INTERNAL CHOICE FOR ANY ONE OF THE 03 MARKS QUESTION.
DIFFICULTY LEVEL EASY:-30% ±5% AVERAGE:-50% ±5% DIFFICULT :-20% ±5%
PRACTICALS
CONTENT FIRST-TERM SECOND-TERM
VOLUMETRIC ANALYSIS 6 8
NATURAL ORGANIC COMPOUND 2 -------
INORGANIC COMPOUND ----- 10
JOURNAL + VIVA 2 2
MAXIMUM MARKS 10 20÷2=10
DURATION IN MINUTES 90 150
.

Page 1 of 1

SEAT NO:- TABLE NO:-
Goa Board of Secondary & Higher Secondary Education
Alto, Betim – Goa
CHEMISTRY -XI SCIENCE
First Term Practical Examination(2022-23)
MODEL QUESTION PAPER
Date: Duration: 90 Minutes
Session: Max. Marks:10

Instructions:
1) Write your Examination Seat number and laboratory table number on your answer book and
question paper.
2) Get the burette reading and confirmatory tests initialed by the examiner.
3) Check if the number on (i) your table (ii) answer script and (iii) the containers A, B, and D are
the same. If not, report immediately to the examiner.
4) Use of non - programmable calculator is allowed.
Atomic Masses:- H=1, C=12, N=14, O=16, Na =23, S=32, K=39.
-------------------------------------------------------------------------------------------------------------
Q.1. You are provided with two solutions as follows:-
Container A: N/M solution of _______.
Container B: ______ ‘X’___ N/M_______solution of _____.
Using the above solutions, determine:

i) N/M of the solution in container B.
ii) Calculate the Strength of the solution in container B, in terms of g/____ml (06 Marks)

Q.2. Identify the given Natural Organic substance in container D bearing your table number for the
presence of Carbohydrate/Fat or Oil/Protein and report the test that is positive. (02 Marks)

Q.3. Journal + Viva (1+1 Mark) (2 Marks)
****************************************************************
Marking Scheme for First Term Practical Examination-2022-23

Q 1) Volumetric Analysis ( Acid-base titration):………………………………… (06 Marks)
i) Observations : (Burette, pipette/ conical flask, indicator, color change) (1Mark)
ii) Reading (3 Marks)
± 0.2………………………3mks
± 0.3……………………….2 ½ mks
± 0.4……………………….. 2mks
± 0.5……………………….1 ½ mks
± 0.6……………………….1mk
iii) Calculations: (2 Marks)
1. Determination of N/M of Solution B/A..................................................... 1 mk

2. Strength of the solution in container B/A, in terms of g/____ml …........... 1 mk
Q2. Identification and correct reporting of the given Natural Organic substance………(02 Marks)

Q3. Journal + Viva………………………………………………………………1+1= (2 Marks)

CHEMISTRY -XI SCIENCE
SEAT NO:- TABLE NO:-
Goa Board of Secondary & Higher Secondary Education
Alto, Betim – Goa
CHEMISTRY -XI SCIENCE
Second Term Practical Examination(2022-23)
MODEL QUESTION PAPER
Date: Duration: 150 Minutes
Session: Max. Marks:20

Instructions:
1) Write your Examination Seat number and laboratory table number on your answer book and
question paper.
2) Get the burette reading and confirmatory tests initialed by the examiner.
3) Check if the number on (i) your table (ii) answer script and (iii) the containers A, B, and D are
the same. If not, report immediately to the examiner.
4) Use of non - programmable calculator is allowed.

Atomic Masses:- H=1, C=12, N=14, O=16, Na =23, S=32, K=39.
-------------------------------------------------------------------------------------------------------------

Q.1. You are provided with two solutions as follows:-
Container A: g/ mL solution of .
Container B: Impure solution of

Using the above solutions, determine:

i) N/M of the solution in container B.
ii) Calculate the percentage purity of the solution in container B, g of which have
been dissolved per mL. (08 Marks)

Q.2. Analyse the inorganic salt given in container D bearing your table number
qualitatively and detect the cation and anion present. Give a complete
report of all the tests performed. Write the formula of the Compound
detected. (10 Marks)

Q.3. Journal (2 Marks)

************************************************************************

CHEMISTRY -XI SCIENCE
Marking Scheme for Second Term Practical Examination
Q 1) Volumetric Analysis (Acid-base titration): (08 Marks)
i) Observations : (Burette, pipette/ conical flask, indicator, color change) (1Mark)
ii) Equation ………………………………………………………………………(1Mark)
iii) Reading (3 Marks)
± 0.2…….3mks
± 0.3…. …2 ½ mks
± 0.4……2mks
± 0.5…….1 ½ mks
± 0.6…….1mk
iv) Calculations: (3 Marks)
Conversion of g/ V mL to M/N of Solution A............................................ 1 mk
Determination of N/M of Solution B ........................................................... 1 mk
Percentage purity of Solution B… .................................................................1 mk

Q2.Inorganic Qualitative analysis (10 Marks)
1) Preliminary test /Dry test………………………………………… ½ x 8 = 4 mks
2) Wet test for anion: Correct anion… ................................................................. (1 mk)
C.T ..................................................................................... (1mk)
3) Wet test for cation: Correct group… ................................................................. (1mk)
Correct cation .....................................................................( 1 mk)
C.T ..................................................................................... ( 1 mk)
4) Correct formula ....................................................................................... (1 mk)

3. Journal. (2 Marks)
********************************************************************
GUIDELINES FOR CONDUCT OF THE XI-PRACTICALS IN CHEMISTRY -2022-23
1 .Student should report:
(a) Minimum of 4 volumetric exercises.(Acid base titrations)
(b) Minimum of 10 inorganic qualitative analysis.(Same list of salts as given for STD-XII)
(c) Four physical experiments(to be evaluated for viva only)
i. Crystallization of Copper sulphate
ii. Determination of Boiling & Melting point of two separate organic compounds.
iii. Study the shift in equilibrium between ferric ions and thiocynate ions by increasing /decreasing the
concentration of either of the ions/ Study the shift in equilibrium between [Co(H2O)6 ]2+ and
chloride ions by changing the concentration of either of the ions.
iv. Determination of pH of some solutions obtained from fruit juices, solutions of known and varied
concentrations of acids, bases and salts using pH paper and/or universal indicator
(d) Identification of Natural organic substances
Note:
I. Except for fat/oil aqueous solution or suspension of food items containing natural organic
substance to be given and not the direct natural organic substance.

II. Any one of the positive test to be reported

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION,
ALTO - PORVORIM , GOA.
BLUE PRINTAND QUESTIONWISE ANALYSIS OF FIRST QUARTERLY
EXAMINATION QUESTION PAPER OF STANDARD XI SCIENCE

Subject: Chemistry Marks: 20 Duration: 60 Minutes.
OBJECTIVES DIFFICULTY LEVEL
K U A S Easy Average Difficult
Percentage 20 50 20 10 30 50 20
Marks 4 10 4 2 6 10 4
Variation of ± 5% is permitted in the above Objectives and Difficulty Level
Type of qs. Marks
No. of qs. Total
MCQ 12 2
VSA 12 2
SA-I 25 10
SA-2 32 6
11 20
MCQ= MULTIPLE CHOICE QUESTION , VSA= VERY SHORT ANSWER ,

SA-I = SHORT ANSWER I SA-II = SHORT ANSWER II

Q. Type Unit Objective Difficulty Marks Duration
No. Level (Minutes)
1 MCQ 1. Some Basic Concepts of U E 1 3
Chemistry
2 MCQ 3.Classification of Elements U E 1 3
and Periodicity in Properties

3 VSA 1. Some Basic Concepts of K E 1 2
Chemistry
4 VSA 2. Structure of Atom K Av 1 2
5 SA-I 1. Some Basic Concepts of A D 2 6
Chemistry
6 SA-I 1. Some Basic Concepts of K Av 2 5
Chemistry
7 SA-I 2.Structure of Atom A D 2 6
8 SA-I 2.Structure of Atom S Av 2 6
9 SA-I 3.Classification of Elements U Av 2 6
and Periodicity in Properties

10 SA-II 2.Structure of Atom U E 3 8
11* SA-II 3.Classification of Elements U Av 3 8
and Periodicity in Properties

20 55
*CHOICE TO BE PROVIDED ONLY FOR ONE QUESTION OF 3MARKS.
Page1 of 1

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION,
ALTO - PORVORIM , GOA.

MODEL QUESTION PAPER FOR FIRST QUARTERLY TEST (2022-2023)

STD :XI SCIENCE SUBJECT :CHEMISTRY MARKS: 20 DURATION : 60 min

Instructions:
(i) All questions are compulsory. However Q.11 has an internal choice.
(ii) Use logarithm tables for calculations wherever required. Do not use calculator.
(iii) Each question should be attempted only once.
(iv) Section A consists of four questions of 1 mark each.
(v) Section B consists of five questions of 2 marks each.
(vi) Section C consists of two questions of 3 marks each.

SECTION A

Q.1 The empirical formulae of the compounds C6H12 and N2O4 are………….. 1
respectively.
 CH2 and N2O
 CH and NO
 CH2 and NO2
 CH and NO2

Q.2 Considering the elements B, C, N, F and Si the correct order of their 1
nonmetallic character is___________.
 B> C > SI > N > F
 F >N >C> B> Si
 F> N> C> Si > B
 Si > C >B > N > F

Q.3 State the Law of Multiple Proportion. 1

Q.4 What are isoelectronic species? 1

SECTION B

Q.5 Calculate molality of a solution containing 15 g of sodium carbonate 2
dissolved in 500 ml of solution having density of solution as 1gml -1. (Atomic
masses of Na= 23, C =12 and O = 16)

Q.6 Define the following terms: 2
i. One atomic mass unit
ii. one mole

Q.7 If the uncertainty in the measurement of position and momentum 2

of an electron are found to be equal in magnitude , calculate the uncertainty in
the measurement of velocity of the electron .
(Given: h= 6.63 x 10–34kg m2 s–1,mass of electron = 9.11 x 10–31kg)

Q.8 Draw the shapes of the following orbitals and label the regions 2
of zero probability in each.
(i) 2s orbital (ii) 2p orbital

Q.9 Write the general electronic configuration of : 2
(i) s-block elements (ii) d-block elements

SECTION C

Q10 Answer the following : 3
(i) Write the values of ‘n’ and ‘l’ for the electron of the highest energy in the
Sodium atom.
(ii) Determine the number of unpaired electrons in the Ferric ion.
(iii) If the electron and the proton move at the same speed, which one will
have a greater de-Broglie wavelength and why?

Q.11 Identify the element in each case: 3
1) Highest electron gain enthalpy
2) Tendency to achieve Argon electronic configuration by losing one
electron.
3) tendency to achieve Neon electronic configuration by gaining one
electron

OR

Q.11 Identify the element in each case: 3
1) Highest electronegativity
2) tendency to lose three electrons & achieve Neon electronic
configuration
3) tendency to gain one electron & achieve Argon electronic
configuration

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION,
ALTO - PORVORIM , GOA.

ANSWER KEY TO MODEL QUESTION PAPER FOR FIRST QUARTERLY TEST
(2022-2023)

STD :XI SCIENCE SUBJECT :CHEMISTRY MARKS: 20 DURATION : 60 min

Q.1  CH2 and NO2 1

Q.2  F > N > C > B > Si 1

Q.3 When two elements combine to form two or more than two compounds, 1
then the masses of one of the elements which combine with a fixed mass of
the other are in simple whole number ratio.

Q.4 Isoelectronic species are those species which contain the same number of 1
electrons.

Q.5 Molality = no. of moles of solute x 1000 ……(1/2 mark) 2
Weight of solvent in g
Density of solution = mass of solution
Vol of solution
Mass of solution = 1 x 500 = 500 g
Weight of solvent = 500g – 15g = 485 g ……(1/2 mark)
Molality = 15 X 1000 ……(1/2 mark)
106 x 485
= 0.291 m …… (1/2 mark)

Q.6 a) One atomic mass unit is defined as a mass exactly equal to one-twelfth 2
the mass of one carbon - 12 atom.

b) One mole is the amount of a substance that contains as many particles or
entities as there are atoms in exactly 12 g (or 0.012 kg) of the 12C isotope.

Q.7 2

Q.8 2

1 mk 1 mk

Q.9 General electronic configuration 2
i.
s block elements is ns(1−2)
(1−10)
ii. d block elements is (n−1)d ns (0−2)
Q.10 (i) Na atom = 1s2 2s2 2p6 3s1 3
3s1 = highest energy electron
Hence n=3 and l=0 ………………………1 mk

(ii) Ferric ion = 1s2 2s2 2p6 3s2 3p6 3d5.

Five unpaired electrons. ……………………….1 mk

(iii) mass of proton is greater than mass of electron. …..½ mk
Thus wavelength of electron is greater than the wavelength of
proton. …..½ mk

Q.11 1.Chlorine 3
2. Potassium
3. Fluorine

OR

Q.11 1. Fluorine 3
2. Aluminum
3. Chlorine

************************************************************************************

GOA BOARD OF SECONDARY AND HIGHER SECONDARY
EDUCATION PORVORIM – GOA.

BLUEPRINT OF MODEL QUESTION PAPER FOR FIRST TERM EXAM ( 2022 - 2023)

STD : XI SUB : CHEMISTRY MARKS : 40 DURATION : 90 min

OBJECTIVES DIFFICULTY LEVEL
K U S A Eas Average Difficul
y t
Percentage 30 40 10 20 30 50 20
Marks 12 16 4 8 12 20 8

Variation of ± 5 % is permitted in the above Objectives and Difficulty Level

Type of questions Marks Number of Total
questions marks
MCQ 1 4 4
VSA 1 4 4
SA-1 2 11 22
SA-2 3 2 6
LA 4 1 4
Total 22 questions 40 mks

MCQ = Multiple Choice
Question VSA = Very Short
Answer
SA – I = Short Answer I
SA – II = Short Answer
II LA = Long Answer
*Choice to be provided for one question of 2 marks and one question of 4 marks.

NOTE:
Model paper set for first term is subjective type but the subject teacher in consultation with
the Head of the institution may set the paper in same way like XII STD Board first term
paper (All 40 MCQ questions).

GOA BOARD OF SECONDARY AND HIGHER SECONDARY
EDUCATION PORVORIM GOA

BLUEPRINT OF MODEL QUESTION PAPER OF FIRST TERM EXAM - STD XI (2022-23)

SUBJECT : CHEMISTRY MARKS : 40 DURATION : 90 min

Q.No. Type of Unit Objectives Difficulty Marks Duration
Question Level in min.
1.Some basic concepts of
1 MCQ Chemistry. K E 1 2

2 MCQ 9. Hydrogen K E 1 2
12. Organic Chemistry – Some
3 MCQ basic principles and techniques. U Av 1 2
3. Classification of elements
4 MCQ and Periodicity in properties. K E 1 2

5 VSA 2. Structure of atom S E 1 2

6 VSA 2.Structure of atom S Av 1 2

7 VSA 9. Hydrogen K E 1 2

8 VSA 9. Hydrogen U Av 1 2

9 SA - I 2. Structure of atom U Av 2 3
4.Chemical bonding and
10 SA – I Molecular structure. S Av 2 3
4. Chemical bonding and
11 SA – I Molecular structure. K E 2 3
12. Organic Chemistry- Some
12 SA – I basic principles and techniques. A D 2 4
12. Organic Chemistry – Some
13 SA – I basic principles and techniques. U Av 2 3

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION, PORVORIM – GOA.

Q.No. Type of Unit Objectives Difficulty Marks Duration
Question Level in min
1.Some basic concepts of
14 SA – I Chemistry. U Av 2 3
15* SA – I 1.Some basic concepts of
Chemistry . A
OR D 2 5
15* SA - I 1.Some basic concepts of
Chemistry. A
3.Classification of elements
16 SA – I and periodicity in properties. U Av 2 4
3.Classification of elements
17 SA –I and periodicity in properties. A D 2 5

18 SA – I 5.States of matter K E 2 4

19 SA – I 5.States of matter U D 2 5

20 SA – II 2.Structure of atom K E 3 6
12.Organic chemistry – Some
21 SA - II basic principles and techniques. K/U Av 1+2=3 6
22* L A* 4.Chemical Bonding and
Molecular structure. U/A
OR Av 2+2=4 10
22* L A* 4.Chemical Bonding and
Molecular structure. U/A

TOTAL MARKS AND DURATION IN 40mks 80min
MINUTES

*Internal choice

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION,
ALTO - PORVORIM - GOA.
MODEL QUESTION PAPER FOR FIRST TERM EXAM (2022-2023 )
STD : XI SCIENCE DURATION : 90 min
SUBJECT : CHEMISTRY MARKS : 40
—----------------------------------------------------------------------------------------------------------------------
Instructions:
1. All questions are compulsory. However Q. No. 15 & Q. No. 22 has internal choice.
2. Use a logarithmic table for calculations wherever required. Use of calculator is not permitted.
3. Each question should be attempted only once.
4. Section A consists of eight questions of 1 mark each.
5. Section B consists of eleven questions of 2 marks each.
6. Section C consists of two questions of 3 marks each.
7. Section D consists of one question of 4 marks.
—----------------------------------------------------------------------------------------------------------------------

SECTION- A

Q. 1 A given compound always contains exactly the same proportion of elements by 1
weight. This is in accordance with…………….
 Law of definite proportion
 Gay Lussac’s Law
 Law of multiple proportion
 Law of conservation of Mass

Q. 2 Moderator which is used in nuclear reactors is ___________. 1
 Tritium
 Ozone
 Heavy water
 Hydrogen peroxide
The longest chain in the following compound consists ___________
Q. 3 1

 8 carbon atoms
 9 carbon atoms
 6 carbon atoms
 5 carbon atoms
An element of group 1 having 1s² 2s¹ electronic configuration is___________
Q. 4 1
 Lithium
 Sodium
 Potassium
 Caesium

Q. 5 Draw the shape of the 3s orbital and indicate the number of nodes in it. 1

Q.6 Draw a neat labelled diagram representing Rutherford’s scattering experiment. 1

Q.7 Name any two methods used for the removal of permanent hardness of water. 1

Write a chemical reaction for the oxidizing action of hydrogen peroxide on ferrous
Q.8 1
ions in acidic medium.

S E C T I O N -B

Q.9 Two particles ‘A’ and ‘B’ are in motion . If the wavelength associated with 2
particle ‘A’ is 5 x 10 –8 m , calculate the wavelength associated with particle ‘B’ if
its momentum is half of ‘A’.
Q.10 Draw the Lewis electron dot structures for the following molecules. 2
i)H2S
ii)CO2
Using VSEPR theory, deduce the structure of the SF6 molecule.
Q.11 2

Write bond line formulaes for :
Q.12 2
i. Isopropyl alcohol,
ii. 2,3-Dimethyl butanal,
Draw the flow chart diagram showing classification of Isomerism.
Q.13 2

Q.14 Write one point of difference between the following. 2
i) Molarity and Molality
ii) Empirical formula and Molecular formula

Q.15 Calculate the number of moles and amount in grams of Sodium carbonate present 2
in 250 ml of 0.5 M solution.
(Atomic masses of Na=23 , O = 16 , C =12)

OR

Q.15 Concentrated sulphuric acid solution contains 64% of sulphuric acid by mass. 2
Calculate the molarity of the solution given the density of solution as 1.84 g ml -
1
. ( Atomic masses of H=1, O =16, S = 32)

Q.16 Give reason for each of the following : 2
i) Atomic size of Fluorine is smaller than Chlorine
ii) Boron is a non metal whereas Thallium is a metal

How would you explain the fact that the first ionisation enthalpy of Sodium is
Q.17 2
lower than that of Magnesium but its second ionisation enthalpy is higher than
that of Magnesium?
State the following Gas laws
Q.18 2
i. Boyle’s law
ii. Avogadro Law

iii.
Differentiate between Dipole-dipole forces and Dipole-induced dipole forces.
Q.19 2

SECTION- C

Q.20 Answer the following : 3
(i) How many electrons in a Sulphur atom can have n+l =3 values?
(ii) State Heisenberg’s Uncertainty Principle.
(iii) Write the electronic configuration of Chromium atom.
What are electrophiles and nucleophiles ?
Q.21 3
Identify the reagents shown in bold in the following equations as nucleophiles or
electrophiles:

SECTION-D
Q.22 4
i) Give two points of difference between sigma and pi bond.
ii) On the basis of molecular orbital theory ,write the electronic
configuration of oxygen molecule and predict it’s magnetic behaviour
OR
i) Give two points of difference between polar and non-polar covalent
Q.22 4
bond.
ii) On the basis of molecular orbital theory, explain why
Ne2 molecule does not exist.
*******************************************************.

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION
ALTO - PORVORIM , GOA

ANSWER KEY TO MODEL QUESTION PAPER OF FIRST TERM EXAM (2022-23)

STD: XI SCIENCE DURATION: 90 min
SUBJECT: CHEMISTRY MARKS: 40

Q.1  Law of definite proportion 1

Q.2  Heavy water 1

Q.3  6 carbon atoms 1

Q.4  Lithium 1

Q.5 1

Q.6 1

Q.7 i) treatment with washing soda 1
ii) Calgon’s method
iii) ion exchange method
iv) synthetic resin method ( any 2 methods ½ mk each)

Q.8 2Fe2+ + 2H+ +H2O2 —----------> 2Fe3+ +2H2O 1
Reaction ½ mk Balancing ½ mk

Q.9 2

Q.10 2

i. )

ii.

Q.11 2

Q.12 2

1.

2.

Q.13 2

Q.14 i) 2
Molarity Molality

1)The molarity of a given solution is 1) Molality is defined as the total moles
defined as the total number of moles of of a solute contained in a kilogram of a
solute per litre of solution. solvent.
2) Depends on the volume of the whole 2) Depends on the mass of the solvent.
solution. 3) has units of moles/kg.
3) has a unit of moles/litre 4) Does not change with temperature.

4) changes with temperature

ii)

Empirical Formula Molecular formula

An empirical formula represents the The molecular formula shows the exact
simplest whole-number ratio of various number of different types of atoms
atoms present in a compound. present in a molecule of a compound.

Q.15 M = no. of moles of solute x 1000 …………(½ mark) 2
Vol of sol in ml
No. of moles of Na2CO3 = 0.5 x 250
1000
= 0.125 moles ………..(½ mark)
1 mol of Na2CO3 = 106 g …………. (½ mark)
0.125 mol of Na2CO3 = 106 x 0.125 = 13.25 g ………. (½ mark)

OR

Q.15 64% by mass means 64 g of H2SO4 present in 100 g of solution. 2
Volume of solution = Mass
Density
= 100 = 54.34 ml. …….(½ mark)
1.84
No. of moles of H2sO4 = 64 = 0.653 moles ……..(½ mark)
98
M = no. of moles of solute x 1000 …………(½ mark)
Vol of sol in ml
= 0.653 x 1000 = 12.02 M …………(½ mark)
54.34

Q.16 i) Due to shielding effect or new shells added shield the outer electron from getting 2
attracted towards nucleus.
ii) Metallic character increases down the group

Q.17 1st IE of Na is smaller than Mg due to losing one electron it gains stable electronic 2
configuration To remove second electron from stable electronic configuration lot of
energy is required hence the reason.

Q.18 i. At constant temperature, the pressure of a fixed amount (i.e., number of 2
moles n) of gas varies inversely with its volume. This is known as Boyleís
law.
ii. It states that equal volumes of all gases under the same conditions of
temperature and pressure contain equal number of molecules.

Q.19 Dipole-dipole forces Dipole-induced dipole forces 2
i) These forces act between i) This type of attractive force is present between
molecules with permanent dipole. the polar molecule having permanent dipole and
the molecule lacking permanent dipole.
ii) In this type of force, greater the ii) In this type of force, as the size of the
dipole moment of polar molecule molecule or atom increases, the influence of

greater is the magnitude of dipole- permanent electrical dipole on it will also
dipole forces. This effect is known as increase, resulting in the increase in magnitude
Orientation Effect. of these forces. This effect is termed as Induction
Effect.

Q.20 (i) S ( Z = 16 ) = 1s2 2s2 2p6 3s2 3p4 3
For 1s2 n+l value is 1+0 = 1
For 2s2 , it is 2+0 = 2
For 2p6 , it is 2+1 = 3
Also for 3s2 , it is 3+0 = 3, for 3p4 , it is 3+1 = 4.
Hence , 2p6 and 3s2 electrons have n+l =3 i.e 8 electrons.

(ii) It states that it is impossible to determine simultaneously the exact position and
exact momentum/velocity of a moving microscopic body to an accuracy.

(iii) Cr atom (Z= 24) = 1s2 2s2 2p6 3s2 3p6 4s1 3d5

Q.21 Electrophiles are electron-deficient species and can receive an electron pair. On the 3
other hand, nucleophiles are electron-rich species and can donate their electrons.

Here, HO– acts as a nucleophile as it is an electron-rich species, i.e., it is a nucleus-
seeking species.

Here, –CN acts as a nucleophile as it is an electron-rich species, i.e., it is a nucleus-
seeking species.

Q.22 4

Any 2 points of distinction 1mk each
O2 molecule-

Paramagnetic

OR

Any 2 points of distinction 1mk each

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION
PORVORI - GOA

MODEL QUESTION PAPER FOR SECOND TERM EXAM - STD XI ( 2022-2023)

SUBJECT : CHEMISTRY MARKS : 30 DURATION : 90 min
___________________________________________________________________
INSTRUCTIONS :
i. Question No. 1 to Q. No. 12 carry one mark each.
ii. Q. No. 13 to Q. No. 18 carries two marks each.
iii. Q. No. 19 and Q. No 20 carry three marks each.
iv. Each question should be attempted only once.
v. Q. No. 18 and Q.No.20 have internal choices.
vi. Use of calculator is not permitted. However logarithmic tables will be supplied on request.

Q.1 Calculate the Oxidation Number of : 1
(i) Cl in ClO4 –1 (ii) C in C6H12O6

Q.2 State the Le Chatelier's principle. 1

Q.3 Why does benzene undergo electrophilic substitution reactions easily? 1

Q.4 Write the formula of Borax. 1

Q.5 State the Hess’s law of constant heat summation. 1

Q.6 For a reaction: PbO + C →Pb(s) + CO(g) ; ᐃH and ᐃS are 108.4 KJ/mol and 1
190 J/K/mol respectively. Calculate the temperature for the above reaction at
equilibrium.

Q.7 Write chemical equation to show preparation of Diborane using 1
Lithium hydride as a reducing agent.

Q.8 Identify the oxidising and reducing agent in the following reaction. 1
3 CuO + 2 NH3 → 3 Cu + N2 + 2H2O

Q.9 If equilibrium constant Kc value for the forward reaction is 5 what will be 1
value of equilibrium constant Kc for the backward reaction?

Q.10 Draw a neat labeled diagram for enthalpy change during exothermic reactions. 1

Q.11 Arrange the following metals in the order in which they displace each other 1
from the solution of their salts.
Al , Cu, Fe, Mg
[Given : Standard reduction potentials of Al+3 / Al = – 1.66V,
Cu +2/ Cu = 0.34 V, Fe+2 / Fe = – 0.44V and Mg+2 / Mg = – 2.36 V]

Q.12 Name the position isomer of Pent-1-yne. 1

Q.13 Draw a neat diagram of the Daniel Cell .Label the composition of the anode 2
and the cathode in the cell.

Q.14 What do you mean by strong and weak electrolytes? Give an example of each. 2

Q.15 Name the following: 2
i) Strongest reducing agent among the alkali metals.
ii) Compound obtained from Solvay’s process.
iii) Alkaline earth metal which does not give a characteristic flame color.
iv) Oxide of alkaline earth metal which is amphoteric in nature.

Q.16 Compound A ,an alkyne with 3 carbon atoms reacts with HBr and forms 2
compound B. Compound B further reacts with HBr and gets converted to
compound C which is a geminal dihalide.
Write the chemical equation involved and name the compounds B and C.

Q.17 With respect to group 14 answer the following. 2
i) Oxides of carbon.
ii) Composition of producer gas and its significance in Mond's process.

Q.18 What is a buffer solution? Name the two types of Buffer solutions. 2
OR

Q.18 Define the following. 2
1. Lewis base
2. Arrhenius acid

Q.19 Write the equilibrium constant expression for each of the following reactions. 3
In each case, indicate which of the reactions is homogeneous or
heterogeneous with reason.
1. 2CO(g) + O2(g)⇌2CO2(g)
2. Zn(s) + 2HCl(g)⇌ZnCl2(s)+H2(g)

Q.20 Write chemical equations for each of the following and label the major 3
product formed.
i. Benzene is treated with the mixture of Conc HNO3 and Conc H2SO4
at a temperature of 60ºC
ii. Addition of water to ethyne followed by warming with mercuric
sulphate and dil H2SO4 at 333K.
iii. Reaction of Benzene with acetyl chloride in the presence of
anhydrous AlCl3
OR

Q.20 Write chemical equations for each of the following conversions. 3
i. Sodium Benzoate to Benzene
ii. Propyne to Propane
iii. Benzene to Toluene

GOA BOARD OF SECONDARY AND HIGHER SECONDARY EDUCATION
ALTO - PORVORIM , GOA

ANSWER KEY TO MODEL QUESTION PAPER OF SECOND TERM EXAM -STD XI (2022-23)

SUBJECT: CHEMISTRY MARKS : 30 DURATION : 90 min

Q.1 (i) O.N of Cl in ClO4–1 . 1
(O.N of Cl) + 4(O.N of O) = –1
x + 4( – 2) = –1 . Thus x = +7 (O.N of Cl = +7) …….½ mk
(ii) O.N of C in C6H12O6 .
6(O.N of C) + 12( O. N of H ) + 6 ( O. N of O ) = zero
6x + 12( 1 ) + 6 ( – 2) = 0 . Thus x = 0 (O.N of C = 0). ….½ mk

Q.2 Le Chatelier's principle states that when a system in chemical equilibrium is 1
disturbed by a change of temperature, pressure, or a concentration, the system
shifts in equilibrium composition in a way that tends to counteract this change
of variable.

Q.3 Due to the presence of six π electrons, benzene behaves as a rich source of electrons 1
thus being attacked by electrophiles.

Q.4 Na2B4O7.10H2O 1

Q.5 If a reaction takes place in several steps then its standard enthalpy is the sum of the 1
standard enthalpies of the intermediate reactions into which the overall reaction may be
divided at the same temperature.

Q.6 ᐃG = ᐃH - TᐃS 1
At equilibrium ᐃG = 0
TᐃS = ᐃH ……….(½ ) mark
T = 108400 = 570.52 k ……….(½ ) mark
190

Q.7 2BF3 +6LiH —--> B2H6 +6 LiF 1

Q.8 CuO = oxidising agent …….½ mk 1
NH3 = reducing agent. ……..½ mk

Q.9 Ans: ⅕ = 0.2 1
(Equilibrium constant for the reverse reaction is the inverse of the equilibrium
constant for the reaction in the forward direction.)

Q.10 1

Q.11 Mg, Al, Fe, Cu. ( Metals with lesser reduction potentials can displace the metals with 1
higher reduction potentials from their salts)

Q.12 Pent-2-yne 1

Q.13 Diagram …1 mk 2
Labels - ½mk + ½ mk

Q.14 Strong and weak electrolytes are distinguished on the basis of their ability to get 2
ionized in water or any other polar solvents. Strong electrolytes are almost completely
ionized while weak electrolytes are those substances which get ionized only to a small
extent in their solutions.
Examples of strong electrolytes: HCl, NaOH, NaCl etc.
Examples of weak electrolytes: CH3COOH, H2O, NH4OH etc.

Q.15 i) Li 2
ii) Sodium Carbonate
iii) Be or Mg
iv) BeO

Q.16 CH3-C≡CH + HBr -------------> CH3- CBr = CH2 ……..1/2mk 2

CH3- CBr= CH2 + HBr--------------> CH3-C (Br)2-CH3..1/2mk

Compound B is 2-Bromopropene…………1/2 mk

Compound C is 2,2-Dibromopropane………1/2 mk

Q.17 i) CO, CO2 2
ii) CO + N2
In Mond's process Nickel is purified by forming Nickel carbonyl.

Q.18 A buffer solution is one which resists changes in pH when small quantities of an acid 2
or an alkali are added to it.
Acidic buffer & Basic buffer.
OR

Q.18 1. Lewis base are species which donates an electron pair. 2
2. According to Arrhenius theory, acids are substances that dissociates in water to
give hydrogen ions H+(aq)

Q.19 3

a. is said to be homogeneous in nature while b. is heterogeneous in nature.

(two expressions one mark each and one for writing homogenous & heterogeneous)

Q.20 3

i.

Equation ½ mk
Nitrobenzene ½ mk

ii.

equation 1/2mk
Ethanal/Acetaldehyde 1/2mk

iii.
Equation 1/2mk
Acetophenone 1/2mk

OR

Q.20 3

i.

ii.

iii.
Equation ½ mk
Reagents & reaction conditions ½ mk

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