Chemistry · Class 12 Science

Nagaland Nbse Class 12 Chemistry — Real Previous-Year Papers

with complete answers

Real previous-year board papers, year by year — the official exam pattern, the full question paper, and every question solved the concept-first way. Distinct from the chapter-wise textbook bank.

2016–2025
Years of papers: 10
Total Papers: 10
Real Board Papers: 0
Sample papers: 308
Real-paper Q & A: 0
Sample-paper Q & A

Real board-paper questions available, by year

34 Q2025complete

34 Q2024complete

30 Q2023complete

30 Q2022complete

30 Q2021complete

30 Q2020complete

30 Q2019complete

30 Q2018complete

30 Q2017complete

30 Q2016complete

Nagaland Board of School Education 2025 · Set ANNUAL

Real board examination

About this paper

The real Class-12 board examination held in 2025. Every question below is solved the concept-first way. Sample papers are labelled honestly — never shown as a past exam.

Total marks: 70
Questions: 34
Duration: 180 min
Sections: 1

The marks / questions / duration above are the official exam pattern. We currently have 34 of this paper’s questions (100% of the full paper), with 34 fully solved. Questions we couldn’t yet extract or verify are held — never shown as complete.

Sections & marks

Section	Type	Questions	Marks each	Total
ASection A	compulsory	34	—	—
Total		34		70

The question paper

The questions we hold for this paper, laid out by section. Solutions are on the Answers tab.

Board Examination

Chemistry

Nagaland Board of School Education 2025 · Set ANNUAL

Series/Set: ANNUALRoll No. ________

Time Allowed: 3 hoursMaximum Marks: 70

General Instructions

This question paper contains 34 questions divided into 1 sections — A.
Section A comprises 34 questions (compulsory).

Above is the official exam pattern. The questions printed below are those we currently hold for this paper.

Section A

compulsory · 16 of 34 shown

Q1.

Which of the following pairs will not form an ideal solution?

(a) Benzene and Toluene
(b) Ethanol and Acetone
(c) n-hexane and n-heptane
(d) Bromoethane and Chloroethane

[1]

Q2.

The correct statement in a cell of zinc and copper is

(a) zinc acts as cathode and copper as anode
(b) zinc acts as anode and copper as cathode
(c) the standard reduction potential of zinc is more than that of copper
(d) the flow of electrons is from copper to zinc

[1]

Q3.

Which one of the following is a pseudo first order reaction?

(a) Hydrogenation of ethene
(b) Hydrolysis of ethyl acetate in the presence of dilute acid
(c) Combination of H2 and Br2
(d) Decomposition of NH2 on a platinum surface

[1]

Q4.

Which of the following transition metals does not show variable oxidation state?

(a) Ti
(b) Cr
(c) Cu
(d) Sc

[1]

Q5.

Which of the following is a paramagnetic complex?

(a) [Ni(H2O)6]2+
(b) [Ni(CO)4]
(c) [Zn(NH3)4]2+
(d) [Co(NH3)6]

[1]

Q6.

The position of -Br in the compound in CH3-CH=CHC(Br)(CH3)2 can be classified as

(a) allyl
(b) aryl
(c) vinyl
(d) secondary

[1]

Page 1 of 5

Q7.

Salicyaldehyde can be prepared from phenol by (a) Schotten-Baumann reaction (b) Kolbe's reaction (c) Reimer-Tiemann reaction (d) Cannizzaro reaction

[1]

Q8.

Which of the following is not a characteristic of carbonyl compounds? (a) They have a polarized C=O bond. (b) They undergo nucleophilic addition reactions. (c) They show geometric isomerism. (d) They can be reduced to alcohol.

[1]

Q9.

Benzene diazonium chloride on hydrolysis gives (a) phenol (b) chlorobenzene (c) benzene (d) aniline

[1]

Q10.

The only vitamin with metal atom in it is (a) Vitamin A (b) Vitamin K (c) Vitamin B12 (d) Vitamin E

[1]

Q11.

What is ebullioscopic constant?

[1]

Q12.

Why Fe is a transition metal but Hg is not a transition metal?

[1]

Q13.

Write the IUPAC name of K3[Al(C2O4)3].

[1]

Q14.

Why are ethers relatively inert compounds?

[1]

Q15.

Why do amines react as nucleophiles?

[1]

Q16.

Complete the reaction: CH3CH2NH2 + CHCl3 + 3KOH(alc.) → ?

[1]

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Section B

Q1.

2.82 g of glucose (C6H12O6) are dissolved in 30 g of water. Calculate the mole fraction of glucose and water.

[2]

Q2.

The conversion of molecules X to Y follows second order kinetics. If concentration of X is increased to three times, how will it affect the rate of formation of Y?

[2]

Q3.

Which one of the following La(OH)3 and Lu(OH)3 is more basic and why? **OR** Which is a stronger reducing agent Cr2+ or Fe2+ and why?

[2]

Q4.

Write the equation for the preparation of propan-2-ol from Grignard reagent.

[2]

Q5.

I. Define Swarts reactions. II. Write the IUPAC name of the compound ClCH2C≡CCH2Br.

[2]

Q6.

Differentiate between amylose and amylopectin. **OR** Why amino acid behaves like salts in aqueous solution?

[2]

Section C

Q1.

A solution contains 0.896 g of K2SO4 in 500ml solution. Its osmotic pressure is found to be 0.690 atm at 27°C. Calculate the value of Van't-Hoff factor. (R= 0.082atm mol⁻¹K⁻¹). **OR** A 5% solution (by mass) of cane sugar in water has freezing point of 271K. Calculate the freezing point of a 5% glucose in water, if the freezing point of pure water is 273.15K. [Given Kf = 1.86K Kg mol⁻¹].

[3]

Page 3 of 5

Q2.

Represent the galvanic cell in which the reaction takes place- Zn(s) + 2Ag+(aq) → Zn2+(aq) + 2Ag(s). i) Which of the electrode is negatively charged? ii) The carrier of the current in the cell. iii) Write the reaction at each electrode.

[3]

Q3.

If time taken for half of the first order reaction to complete is t1, whereas that for 3/4th of the reaction to complete is t2. How are t1 and t2 related to each other. (log 4 = 0.60) **OR** The rate of a particular reaction triples when temperature changes from 50°C to 100°C. Calculate the activation energy of the reaction. [log 3 = 0.47, R = 8.314 JK⁻¹mol⁻¹].

[3]

Q4.

I. What are heteroleptic complexes? Give example. II. On the basis of crystal field theory, write the electronic configuration of d5 ion for high spin complex. III. Draw the geometrical isomers of [Co(NH3)Cl(en)2]2+.

[3]

Q5.

I. Show the preparation of 1-iodobutane from but-1-ene. II. Write the SN2 mechanism for the reaction of chlorobutane to butanol.

[3]

Q6.

Explain Kolbe's reaction with the chemical equation involved in it. **OR** What happens when- i) anisole reacts with HI? ii) ethanol reacts with CH3COCl/pyridine? iii) phenol is oxidized with Na2Cr2O7/H+?

[3]

Q7.

Complete the following reaction: i) CH3MgCl + CO2 --(ether)--> ? --(H3O+)--> ? ii) 2 CH3-CHO --(dil. NaOH, Δ)--> ? iv) CH3-CH=CH-COCl --(H2, Pd-BaSO4)--> ?

[3]

Q8.

(i) Name the reaction when benzene diazonium chloride is treated with cupruous chloride. (ii) Why are aryl diazonium ion more stable than akyl diazonium ion?

[3]

Page 4 of 5

Q9.

(i) What is isoelectric point? (ii) What is the effect of denaturation on the structure of proteins?

[3]

Section D

Q1.

(i) State Kohlrausch law of independent migration of ions. Write one application. (ii) The conductivity of 0.001028 mol L⁻¹ acetic acid is 4.95×10⁻⁵Scm⁻¹. Calculate its dissociation constant if Λ°m for acetic acid is 390.5 Scm² mol⁻¹. **OR** (i) Write the oxidation and reduction reaction for corrosion of iron in atmosphere. (ii) Calculate how long it will take to deposit 1 g of chromium when a current of 1.25A, flows through a solution of chromium III sulphate. (Molar mass of Cr = 52, F = 96500C).

[5]

Q2.

Explain the following with reason:- i) Transition metals and their compounds show catalytic activities. ii) Actinoid contraction is greater from element to element than lanthanoid contraction. iii) Sc3+ is colourless whereas Ti3+ is coloured in an aqueous solution.

[5]

Q3.

(i) Convert benzene to acetophenone. (ii) Write the chemical reaction of Tollen's reagent with propanone and propanal. (iii) Write the reaction involved in Wolf-Kishner reduction. **OR** (i) Show the formation of ketal from acetone. (ii) Why are the boiling point of carboxylic acids higher than the corresponding alcohol? (iii) Arrange the following compounds in the increasing order of their acidic strength: ClCH2COOH, CH2ClCH2COOH and FCH2COOH.

[5]

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