Goa Board Class 12 Question Paper 2025 Chemistry

2025 II 20 0930 Seat No.

Time : 3 Hours CHEMISTRY
Subject Code

H 4 7 0 3
Total No. of Questions : 35 (Printed Pages : 11) Maximum Marks : 70

INSTRUCTIONS : (i) There are 35 questions to answer. However Q. Nos. 17,

32, 33, 34 and 35 have internal choice.

(ii) Answer each question only once.

(iii) Use of calculator is not permitted. Logarithm tables shall

be supplied on request.

(iv) For Question Nos. 1 to 8, select and write the correct

alternative from the options given below the statement.

(v) Question Nos. 1 to 13 carry one mark each.

(vi) Question Nos. 14 to 25 carry two marks each.

(vii) Question Nos. 26 to 32 carry three marks each.

(viii) Question Nos. 33 to 35 carry four marks each.

H-4703 1 P.T.O.

1. A hormone that contains lodine is ..................... . 1

• adrenaline

• thyroxine

• testosterone

• insulin

G for a reaction when a catalyst is added
to it ? 1

• It increases

• It decreases

• It remains unchanged

• It is undefined on addition of catalyst

3. The compound CH3CH2C(CH3)2CH2Cl is a ....................... 1

• primary alkyl halide

• primary allyl halide

• secondary alkyl halide

• secondary benzyl halide

4. Which of the following statements is true regarding the conductivity of
electrolytic solutions ? 1

• It is independent of the size of the ions

• It is independent of the viscosity of the solution

• It decreases with temperature

• It depends on the solvation of ions present in the solution

H-4703 2

• 2º > 1º > 3º

• 1º > 2º > 3º

• 3º > 1º > 2º

• 3º > 2º > 1º

6. The metallic radii of some transition elements are given below :

Element Iron Cobalt Nickel Copper

Metallic radii/pm 126 125 125 128

An element that has the highest density from the above is .................. . 1

• Nickel

• Cobalt

• Iron

• Copper

7. The product formed in Aldol condensation is ........................ . 1

• an , unsaturated ester

• an -hydroxy aldehyde or ketone

• a -hydroxy acid

• a -hydroxy aldehyde or ketone.

H-4703 3 P.T.O.

• HCHO < CO2 < CH4 < Ar

• Ar < CO2 < CH4 < HCHO

• Ar < CH4 < CO2 < HCHO

9. Write the chemical name of Vitamin C. 1

10. Draw the structure of the chromate ion. 1

11. Write the structural formula of 2-ethoxy-2-methylpropane. 1

12. Define : Activation energy. 1

13. Identify the structure of the missing component in the given reaction

sequence : 1

Toluene conc.HNO3 + conc.H2SO4 ? Fe/HCl 4-aminotoluene

14. Draw a neat labelled diagram of the Hydrogen-Oxygen fuel cell by specifying

the electrolyte and the electrode material used. 2

15. State Faraday’s first law of electrolysis. 2

Calculate for CA Cl2 from the given data :

ºm for Ca+2 = 119.0 S cm2 mol–1 and ºm for Cl–1 = 76.3 S cm2 mol–1

16. Write the IUPAC name of each of the following complexes : 2

(i) K3[Al(C2O4)3]

(ii) [Cr (NH3)4 (H2O)2]Cl3

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17. On the basis of Valence Bond theory, deduce the type of hybridisation and

geometry of the high spin complex [CoF6]–3. 2

Or

17. On the basis of Valence Bond theory, deduce the type of hybridisation and

magnetic character of the tetrahedral complex [Ni(CO)4]. 2

18. Select the correct compound from each of the given pairs.

(i) Which halogen compound from the following will undergo SN2 reaction

faster ? 2
Cl Cl

(ii) Which molecule from the given pair is chiral ?

CH3CH2CH2CH2Br and CH3CH(Br)CH2CH3

19. Write one point of difference as specified in each case : 2

(i) Essential amino acids and non-essential amino acids on the basis of

their synthesis.

(ii) DNA and RNA with respect to the sugar moiety present in them.

20. Name the following : 2

(i) An element of the 3d series that exhibits maximum number of

Oxidation states.

(ii) An alloy which consists of 95% lanthanoid metal along with iron and

other trace elements.

H-4703 5 P.T.O.

21. Identify the structure of the final product ‘X’ and ‘Y’ formed in each of the

following reactions : 2

hydroboration-oxidation
(i) C6H5 – CH = CH2 ‘X’

conc . H SO at 413 K
(ii) CH3CH2CH2–OH 2 4 'Y'

22. Write chemical equations for each of the following reactions : 2

(i) Phenol is treated with Bromine water.

(ii) Vapours of ethyl alcohol are passed over heated copper at 573 K.

23. Define azeotropes. State the type of azeotrope formed by a solution exhibiting

positive deviation from Raoult’s Law. 2

24. Identify the structure or name of Compounds ‘P’ and ‘Q’ in the following

reactions : 2

(i) CH3CH2-CONH2 + Br2 + alcoholic NaOH Compound ‘P’ +Na2CO3 +

NaBr + H2O

(ii) + C2H5 – NH2 Compound ‘Q’ + HCl

25. For a reaction, H2 + Cl2 h 2 HCl, the rate law is 2

Rate = k

(i) Write the Order of the reaction.

(ii) State the Unit of rate constant ‘k’ for the above reaction.

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26. Half life period of a first order reaction is 693 seconds. Calculate the
following : 3
(i) Rate constant ‘k’.
(ii) Time required for 90% completion of this reaction in minutes.
27. Identify the Name of the reactions which are illustrated by the following
chemical equations : 3
(i) C6H5Br + 2Na + CH3Br C6H5 – CH3 + 2NaBr
Cu 2Cl2
(ii) C6 H 5 N (2 )Cl – + HCl C6 H5Cl + N2
(iii) CH3CH2Cl + AgF CH3CH2F + AgCl
28. Answer the following : 3
(i) Draw and label the facial (fac–) and meridional (mer-) isomers of
[Co (NH3)3(NO2)3].
(ii) Write one point of difference between homoleptic and heteroleptic
complexes.
29. Answer the following :

(i) Write the IUPAC name for : 3

(ii) Name the foul smelling compound obtained when aniline is subjected
to Carbylamine Reaction.

(iii) State two factors that affect the basic strength of amines.

30. Name the following : 3

(i) The linkage between two monosaccharide units in carbohydrates.

(ii) A nonreducing disaccharide which upon hydrolysis gives equimolar
mixture of D(+) glucose and D(-) fructose.

(iii) The product obtained when glucose is heated with HI.
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31. An alkene having molecular formula C5H10 upon ozonolysis and further
decomposition with zinc and water forms Compound ‘B’ and Compound ‘C’

as products. Compound ‘B’ gives Fehling’s test as well as a positive iodoform

test. Compound ‘C’ gives a positive iodoform test and not the Fehling’s test.

Write the appropriate chemical equation involved in the formation of

Compounds B and C from the alkene. Also write the names of Compounds

B and C. 3

32. With respect to ‘d’ and ‘f’ block elements, answer the following : 3

(i) Predict which of the following ions will be coloured in aqueous

solution ?

Cr3+, Zn2+, Cu1+, Ni2+

(ii) Write the complete ionic equation for the oxidising action of acidified

permanganate ions on ferrous ions.

(iii) State the reason : Actinoid contraction is greater from element to

element than Lanthanoid contraction.

Or

32. With respect to ‘d’ and ‘f’ block elements, answer the following : 3

(i) Predict which of the following ions will exhibit magnetic moment ?

Sc3+, Fe2+, Ti4+, Co2+

(ii) Write the complete ionic equation for the conversion of dichromate ion

into chromate ion.

(iii) State the reason : Zirconium and Hafnium have similar atomic radii.

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33. With respect to Solutions, answer the following : 4

(i) Draw a neat labelled graph to represent the dependence of Vapour
pressure on mole fraction of a component of a binary solution
exhibiting ideal behaviour.

(ii) Calculate the Osmotic pressure of a 5% (w/v) solution of urea (molar

mass 60) at 27ºC.

(Given : R = 0.083 litre bar K–1mol–1)

Or

33. With respect to Solutions, answer the following : 4

(i) Draw a neat labelled graph to represent the elevation in boiling point
of a solvent upon the addition of a non-volatile solute.

(ii) Calculate the mole fraction of KI in an aqueous solution containing
20% of KI by mass.

(Given : At. mass of K = 39, I = 127, H = 1, O = 16)

34. On the basis of the given data, answer the questions below : 4

A galvanic cell is set up at 25ºC with the following half cells.

Ag1+(10–3 M)/Ag(s) and Cu2+ (10–1 M)/Cu(s)

(Given : Eº Ag1+/Ag = 0.80 V, EºCu2+/Cu = 0.34 V)

(i) Write the net cell reaction taking place in this cell.

(ii) Is it possible to store a solution of Copper sulphate in a silver
vessel ?
(iii) Calculate Ecell at the given concentrations.
2.303 RT
(Consider the value of as 0.06 in the calculation)
F

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Or

34. On the basis of the given half reactions, answer the questions below : 4

Al3+(aq) + 3e– Al(s) ............... Eº = – 1.66V

Ni2+(aq) + 2e– Ni(s) ............... Eº = – 0.25 V

(i) Represent an electrochemical cell using Nickel and Aluminium

electrodes as per cell conventions.

(ii) Among Ni and Al, which is a better reducing agent ?

(iii) Calculate the equilibrium constant (Kc) for the cell reaction.

2.303 RT
(Consider the value of as 0.06 in the calculation)
F

35. Answer the following : 4

(i) Select the carboxylic acid from the following having the highest acid

strength :

4-nitrobenzoic acid, benzoic acid, 4-methoxybenzoic acid

(ii) Write the chemical equation for the preparation of an oxime from

acetaldehyde.

(iii) Identify the reagent/s and the final product in each of the following

Name reactions :

(a) Etard Reaction with methylbenzene.

(b) Clemmensen reduction of acetone.

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Or

35. Answer the following : 4

(i) Select a compound that is most reactive towards nucleophilic addition

reaction from the following :

Acetone, acetaldehyde, propionaldehyde.

(ii) Write the chemical equation involved when Sodium acetate is heated

with sodalime.

(iii) Identify the reagent/s and the main reactant in each of the following

Name reactions :

(a) Preparation of acetophenone by Friedel Craft’s acylation.

(b) Preparation of -bromopropanoic acid by Hell Volhard Zelinsky

Reaction.

H-4703 11 P.T.O.