Kerala Plus One Question Paper 2023 Chemistry

FIRST YEAR

Kerala Board
Question Paper
2023

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Reg. No. : ......................................
Name : ...........................................
FY-425
FIRST YEAR HIGHER SECONDARY EXAMINATION, MARCH 2023

Part – III Time : 2 Hours
CHEMISTRY Cool-off time : 15 Minutes
Maximum : 60 scores

General Instructions to Candidates :
 There is a ‘Cool-off time’ of 15 minutes in addition to the writing time.
 Use the ‘Cool-off time’ to get familiar with questions and to plan your answers.
 Read questions carefully before answering.
 Read the instructions carefully.
 Calculations, figures and graphs should be shown in the answer sheet itself.
 Malayalam version of the questions is also provided.
 Give equations wherever necessary.
 Electronic devices except non-programmable calculators are not allowed in the
Examination Hall.

 
    15  ‘  ’ .
 ‘  ’    
 .
      .
    .
  , , ,   
.
   .
    .
     
    .

1 P.T.O.

Answer any 4 questions from 1 to 5. Each carries 1 score. (4  1 = 4)

1. The number of moles of CO2 present in 220 g of CO2 is _______.

2. The IUPAC name of a compound with atomic number 104 is _____.

3. Which among the following is isoelectronic with O2– ?

(a) Na (b) Ca2+

(c) F– (d) Mg

4. Write the IUPAC name of the compound given below :
CH3 – CH2 – CH – CH2 – CHO
|
OH

5. Among the possible conformations of ethane, the most stable form is _______.

Answer any 8 questions from 6 to 15. Each carries 2 scores. (8  2 = 16)
6. (i) Define Molarity. (1)
(ii) State the law of definite proportions. (1)

7. Write the de Broglie equation and explain the terms.

8. (i) Write the n and l values of a 3s electron. (1)
(ii) Which among the following is the correct electronic configuration of Nitrogen
(Z = 7). Name the rule that forms the basis of your answer.

(a) 1s2 2s2 2px2 2py1 2pz0

(b) 1s2 2s2 2px1 2py1 2pz1 (1)

FY-425 2

1  5    4  .
1  . (4  1 = 4)

1. 220 g CO2    _______ .

2.   104    IUPAC  _____ .

3.   O2–     ?
(a) Na (b) Ca2+
(c) F– (d) Mg

4.     IUPAC   :
CH3 – CH2 – CH – CH2 – CHO
|
OH

5.       _______
.

6  15    8  .
2  . (8  2 = 16)
6. (i)  . (1)
(ii)   . (1)

7.      .

8. (i) 3s  n  l   . (1)
(ii)    (Z = 7)  
 ?     
.
(a) 1s2 2s2 2px2 2py1 2pz0
(b) 1s2 2s2 2px1 2py1 2pz1 (1)

FY-425 3 P.T.O.

9. (i) State modern periodic law. (1)

(ii) How does atomic radius vary down a group ? (1)

10. (i) What is ionization enthalpy ? (1)

(ii) First ionization enthalpy of Nitrogen is greater than that of Oxygen. Why ? (1)

11. State Hess’s Law. Illustrate it with an example.

12. (i) Write the Bronsted – Lowry concept of acids and bases. (1)

(ii) Define pH. (1)

13. What is decomposition reaction ? Give an example for it.

14. Write the IUPAC name of the compound given below. Identify the number of sigma
and pi bonds present in it.

CH2 = CH – CH = CH2

15. Complete the following reactions :

Ni
(i) + 3H2 — _______. (1)


(ii) 2C2H5 – Br + 2Na ether
  _____ + 2 NaBr. (1)

Answer any 8 questions from 16 to 26. Each carries 3 scores. (8  3 = 24)

16. (i) Write the relationship between empirical formula and molecular formula. (1)

(ii) Calculate the amount of Oxygen required for the complete combustion of 48 g
of methane. (2)

FY-425 4

9. (i)    . (1)
(ii)         
 ? (1)

10. (i)    ? (1)
(ii)     
.  ? (1)

11.     .

12. (i)    -
 . (1)
(ii) pH  . (1)

13.    ?   .

14.    IUPAC  .  
,    .
CH2 = CH – CH = CH2

15.      :
Ni
(i) + 3H2 — _______. (1)


(ii) 2C2H5 – Br + 2Na  _____ + 2 NaBr. (1)

16  26    8  .
3  . (8  3 = 24)
16. (i)     
 . (1)
(ii) 48 g      
. (2)
FY-425 5 P.T.O.

17. Write the observations and conclusions of Rutherford’s -ray scattering experiment.

18. Give reason for the following :

(i) Na+ is smaller in size than Na atom. (1)

(ii) P forms PCl5 while N cannot form NCl5. (1)

(iii) The electron gain enthalpy of Cl is more negative than that of F. (1)

19. (i) What is dipole moment ? (1)

(ii) Dipole moment of NH3 is higher than that of NF3. Why ? (2)

20. (i) What is octet rule ? (1)

(ii) Write any two drawbacks of octet rule. (2)

21. (i) State the second law of thermodynamics. (1)

(ii) What is entropy ? (1)

(iii) Write how spontaneity of a chemical reaction is related with Gibb’s energy
change ? (1)

22. (i) What is buffer solution ? (1)

(ii) Write any one example for acidic and basic buffer. (1)

(iii) What is common ion effect ? (1)

23. Balance the following redox reaction by oxidation number method (Basic medium) :

MnO4– (aq) + I– (aq)  MnO2 + I2
(s) (s)

FY-425 6

17.  -   
 .

18.     :
(i) Na+  Na   . (1)
(ii) P  PCl5   N  NCl5 
. (1)
(iii) F       
  Cl . (1)

19. (i)    ? (1)
(ii) NH3    NF3   .  ? (2)

20. (i)    ? (1)
(ii)      . (2)

21. (i)    . (1)
(ii)    ? (1)
(iii)      
   ? (1)

22. (i)     ? (1)
(ii)       . (1)
(iii)     ? (1)

23.     
   ( )
MnO4– (aq) + I– (aq)  MnO2 + I2
(s) (s)

FY-425 7 P.T.O.

24. How will you detect the presence of the following elements in an organic compound
by Lassaigne’s test ?
(i) Nitrogen (1½)
(ii) Sulphur (1½)

25. (i) What is the major product formed when HBr is added to propene ? (1)
(ii) Name the rule used to choose the major product and state the rule. (2)

26. Explain the following reactions of alkanes :
(i) Isomerisation (1)
(ii) Aromatization (1)
(iii) Pyrolysis (1)

Answer any 4 questions from 27 to 31. Each carries 4 scores. (4  4 = 16)
27. (i) Write the name of any four series of spectral lines in the atomic spectrum of
Hydrogen. (2)
(ii) What are the limitations of Bohr’s model of atom ? (2)

28. (i) Write any two salient features of molecular orbital theory. (2)
(ii) Match the molecules given in Column A with their hybridization given in
Column B : (2)

A B

I. BeCl2 a. sp3d

II. PCl5 b. sp3

III. CH4 c. sp2

IV. BCl3 d. sp

e. sp3d2

FY-425 8

24.      
   
 
  ?
(i)  (1½)
(ii)  (1½)

25. (i)  HBr     
   ? (1)
(ii)      
 . (2)

26.      :
(i)  (1)
(ii)  (1)
(iii)   (1)

27  31    4  .
4  . (4  4 = 16)
27. (i)      
  . (2)
(ii)      ? (2)

28. (i)      
. (2)
(ii)  A    B  
   : (2)
A B
I. BeCl2 a. sp3d
II. PCl5 b. sp3
III. CH4 c. sp2
IV. BCl3 d. sp
e. sp3d2

FY-425 9 P.T.O.

29. (i) What is standard enthalpy of formation ? (1)

(ii) Calculate the standard enthalpy of formation of CH3 – OH(l) from the following
data :

3
CH3 – OH(l) + O → CO2(g) + 2H2O(l), rHo = –726 kJ/mol
2 2(g)

C(graphite) + O2(g) → CO2(g), CHo = –393 kJ/mol

1
H2(g) + O → H2O(l), f Ho = –286 kJ/mol (3)
2 2(g)

30. (i) What is homogeneous equilibria ? Give an example for it. (2)

(ii) Write the relationship between KP and KC for the reaction H2 + I2 2HI. (2)

31. (i) Write the name of any two methods for the purification of organic compounds. (1)

(ii) Which purification method is used to separate glycerol from spent lye ? (1)

(iii) What is electromeric effect ? Write two types of electromeric effect. (2)

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FY-425 10

29. (i)     ? (1)

(ii)     CH3 – OH(l)  
   :

3
CH3 – OH(l) + O → CO2(g) + 2H2O(l), rHo = –726 kJ/mol
2 2(g)

C(graphite) + O2(g) → CO2(g), CHo = –393 kJ/mol

1
H2(g) + O → H2O(l), f Ho = –286 kJ/mol (3)
2 2(g)

30. (i)    ?   . (2)

(ii) H2 + I2 2HI   KP  KC  

   . (2)

31. (i)     
  . (1)

(ii)       
  ? (1)

(iii)    ?  
  . (2)

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FY-425 11 P.T.O.

FY-425 12