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Tamil Nadu State Board · CLASS 12th · Chemistry

TAMIL NADU STATE BOARD CLASS 12 CHEMISTRY 2026

39 questions from this CLASS 12th Chemistry paper. Log in as a CLASS 12th student to view solutions.

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Q1 mcq 1 mark
Electrochemical process is used in the extraction of which of the following element?
  • A. Sodium
  • B. Iron
  • C. Silver
  • D. Lead

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Q2 mcq 1 mark
The stability of $+1$ oxidation state increases in the sequence __________.
  • A. $\mathrm{In < Tl < Ga < Al}$
  • B. $\mathrm{Al < Ga < In < Tl}$
  • C. $\mathrm{Ga < In < Al < Tl}$
  • D. $\mathrm{Tl < In < Ga < Al}$

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Q3 mcq 1 mark
$\mathrm{XeF_6}$ on complete hydrolysis produces:
  • A. $\mathrm{XeO_3}$
  • B. $\mathrm{XeOF_4}$
  • C. $\mathrm{XeO_2}$
  • D. $\mathrm{XeO_2F_2}$

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Q4 mcq 1 mark
Which of the following statements is incorrect?
  • A. $\mathrm{Co^{3+}}$ and $\mathrm{Fe^{2+}}$ have same number of unpaired electrons.
  • B. Of all the known elements, Silver has the highest electrical conductivity at room temperature.
  • C. To form a substitute alloy, the difference between the atomic radii of solvent and solute should be less than 15%.
  • D. If the standard electrode potential ($E^\circ$) of a metal is large and negative, the metal is a powerful oxidising agent.

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Q5 mcq 1 mark
How many geometrical isomers are possible for $[\mathrm{Pt(Py)(NH_3)(Br)(Cl)}]$?
  • B. 3
  • C. 15
  • D. 4

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Q6 mcq 1 mark
Assertion: Due to Frenkel defect, density of the crystalline solid decreases. Reason: In Frenkel defect, cation and anion leaves the crystal.
  • A. Assertion is true but Reason is false.
  • B. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
  • C. Both Assertion and Reason are false.
  • D. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

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Q7 mcq 1 mark
The half life period of a radioactive element is 140 days. After 560 days 1 g of element will be reduced to :
  • A. $\frac{1}{8}$ g
  • B. $\frac{1}{2}$ g
  • C. $\frac{1}{16}$ g
  • D. $\frac{1}{4}$ g

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Q8 mcq 1 mark
The pH of sodium formate solution in terms of $K_a$ and the concentration of the electrolyte is :
  • A. $\mathrm{pH = 7 - \frac{1}{2}pK_a - \frac{1}{2}\log C}$
  • B. $\mathrm{pH = 7 - \frac{1}{2}pK_a + \frac{1}{2}\log C}$
  • C. $\mathrm{pH = 7 + \frac{1}{2}pK_a + \frac{1}{2}\log C}$
  • D. $\mathrm{pH = 7 + \frac{1}{2}pK_a - \frac{1}{2}\log C}$

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Q9 mcq 1 mark
The molar conductivity of a $0.5\ \mathrm{mol\ dm^{-3}}$ solution of $\mathrm{AgNO_3}$ with specific conductance $5.76\times10^{-3}\ \mathrm{S\ cm^{-1}}$ at 298 K is :
  • A. $0.086\ \mathrm{S\ cm^2\ mol^{-1}}$
  • B. $2.88\ \mathrm{S\ cm^2\ mol^{-1}}$
  • C. $28.8\ \mathrm{S\ cm^2\ mol^{-1}}$
  • D. $11.52\ \mathrm{S\ cm^2\ mol^{-1}}$

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Q10 mcq
On which of the following properties does the coagulating power of an ion depend ?
  • A. The magnitude of the charge on the ion alone.
  • B. Both magnitude and sign of the charge on the ion.
  • C. The sign of charge on the ion alone.
  • D. Size of the ion alone.

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Q11 mcq
Propan-2-ol on reaction with anhydrous ZnCl$_2$ and concentrated HCl gives __________.
  • A. 1-chloropropane
  • B. Ethyl chloride
  • C. 2-chloro-2-methyl propane
  • D. 2-chloropropane

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Q12 mcq
$\mathrm{CH_3CH_2}$ $\xrightarrow[(ii)\ Zn/H_2O]{(i)\ O/NH_2}$ $X\to Y$ 'Y' is:
  • A. Hexamethylene tetramine
  • B. Formaldehyde
  • C. Oxime
  • D. Diacetone ammonia

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Q13 mcq
$\mathrm{C_6H_5NO_2}$ $\xrightarrow[273K]{\mathrm{Sn/HCl}}$ A $\xrightarrow[283K]{\mathrm{NaNO_2/HCl}}$ B $\xrightarrow{\mathrm{H_2O}}$ C 'C' is:
  • A. $\mathrm{C_6H_5CHO}$
  • B. $\mathrm{C_6H_5OH}$
  • C. $\mathrm{C_6H_5NH_2}$
  • D. $\mathrm{C_6H_5CH_2OH}$

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Q14 mcq
α-D(1) Glucose and β-D(1) Glucose are:
  • A. Enantiomers
  • B. Epimers
  • C. Conformational isomers
  • D. Anomers

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Q15 mcq
Drugs that bind to the receptor site and inhibit its natural function are called __________.
  • A. enzymes
  • B. antagonists
  • C. molecular targets
  • D. agonists

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Q16 short answer
What is calcination ? Give an example.

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Q17 short answer
Mention the type of hybridisation in the following compounds. (a)BrF$_5$ (b)BrF$_3$

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Q18 short answer
Give the differences between double salts and coordination compounds.

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Q19 short answer
Write the rate law for the reaction in which the order with respect to the reactants X, Y and Z are $1/2$, $3/2$ and zero respectively.

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Q20 short answer
Explain the method by which colloidal solutions of ink and graphite are prepared.

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Q21 short answer
How will you convert phenol to phenolphthalein ?

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Q22 short answer
Give the tests for carboxylic acid group.

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Q23 short answer
How do antiseptics differ from disinfectants ?

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Q24 short answer
Calculate the pH of 1.5×10$^{-3}$ M solution of Ba(OH)$_2$.

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Q24 short answer
Calculate the pH of $1.5\times10^{-3}$ M solution of $\mathrm{Ba(OH)_2}$.

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Q25 short answer
Give the basic requirement for vapour phase refining.

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Q26 short answer
Give the electronic configuration of Ce$_{41}$ and Co$_{21}$.

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Q27 mcq
Which type of isomerism is exhibited by the following compounds ?
  • A. [Co(NH$_3$)$_4$Br$_2$]Cl and [Co(NH$_3$)$_4$ClBr]Br
  • B. [Co(NH$_3$)$_5$NO$_2$] and [Co(NH$_3$)$_5$ONO]
  • C. [Pt(NH$_3$)$_4$][PdCl$_4$] and [Pd(NH$_3$)$_4$][PtCl$_4$]

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Q28 short answer
Calculate the percentage efficiency of packing in case of body centered cubic crystal.

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Q29 short answer
Prove that in case of first order reaction $t_{99.9\%}=10 t_{1/2}$.

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Q30 short answer
List any three characteristics of catalysts.

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Q31 short answer
What are harmones ? Give examples.

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Q32 short answer
How is terylene prepared ?

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Q33 long answer
An organic compound (A) with molecular formula C$_2$H$_7$N reacts with nitrous acid to form compound (B) which is unstable. Hence compound (B) gets converted to compound (C). Compound (C) is used as a substitute for petrol. Identify compounds (A), (B) and (C).

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Q34 long answer 5 marks
(a)(i)Write a short note on Gravity Separation process. (ii)Sulphuric acid is a dehydrating agent. Explain with suitable examples. OR (b)(i)Give any three uses of silicones. (ii)Write a short note on Fischer Tropsch synthesis.

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Q35 long answer 5 marks
(a)What is Lanthanoid contraction ? What are the causes and effects of Lanthanoid contraction ? OR (b)Based on Valence bond theory, explain why the geometry of [Ni(CO)$_4$] is tetrahedral and [Ni(CN)$_4$]$^{2-}$ is squareplanar.

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Q36 long answer 5 marks
(a)(i)Differentiate crystalline solids and amorphous solids. (ii)Explain the rate determining step with an example. OR (b)Derive an expression for Ostwald’s dilution law.

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Q37 long answer 5 marks
(a)(i)Explain the thermodynamics of cell reactions. (ii)Why salt bridge is used in Galvanic cells ? OR (b)How does diethyl ether react with the following ? (i)Cl$_2$/light (ii)dil H$_2$SO$_4$/H$_2$O (iii)CH$_3$COCl/anhydrous ZnCl$_2$

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Q38 long answer
(a)Explain the mechanism of Cannizaro reaction. OR (b)(i)How will you convert benzene diazonium chloride to biphenyl ? Give the name of the reaction. (ii)How will you confirm the presence of keto group at C-2 carbon in Fructose molecule ?

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