List of top Questions asked in UP Board XII

Which of the following is the most basic compound?

Which of the following complexes exhibit linkage isomerism?

The chemical name of vitamin \( B_1 \) is

Which of the following ions has highest magnetic moment?

Read the following assertion and reason and choose the correct alternative.
Assertion: Elevation in boiling point for two isotonic solutions is same.
Reason: Boiling point depends upon the concentration of the solute.

(b) (i) Describe any one method for the identification of primary, secondary and tertiary amines. Also write the chemical reactions. (ii) Write a short note on Gabriel Phthalimide Synthesis. (3+2=5)
OR
How will you obtain (write chemical equations only): (i) Benzene diazonium chloride from Aniline (ii) Methylamine from Acetamide (iii) Aniline from Nitrobenzene. (2+1½+1½=5)

(a) Write short notes on the following: (i) Cannizzaro's reaction (ii) Aldol condensation (iii) Gattermann-Koch reaction. (2+1½+1½=5)
OR
How will you obtain (write chemical equations only): (i) Benzaldehyde from Toluene (ii) Benzamide from Benzoic acid (iii) Phthalimide from Phthalic acid (iv) m-nitrobenzaldehyde from Benzaldehyde (v) Benzaldehyde from Benzene. (1+1+1+1+1=5)

(i) Explain the mechanism of the formation of ethanol by acid catalyzed hydration of ethene. (ii) Explain hydroboration-oxidation reaction with an example. (2½+2½=5)
OR
What happens when? (Write chemical equations only) (i) Ethyl bromide reacts with sodium ethoxide. (ii) Phenol is heated with conc. HNO₃ in the presence of conc. H₂SO₄. (iii) Methoxybenzene is heated with acetyl chloride in the presence of anhydrous AlCl₃. (iv) Phenol reacts with chloroform in the presence of aqueous NaOH. (v) Ethyl methyl ether is heated with conc. HI. (1+1+1+1+1=5)

Compare the lanthanoid and actinoid elements with reference to the following: (i) Atomic and ionic sizes (ii) Oxidation state. (1½+1½=3)

(i) Discuss the violet colour of the complex \( [\text{Ti}(\text{H}_2\text{O})_6]^{3+} \) on the basis of crystal field theory.
(ii) Explain with reason that \( [\text{NiCl}_4]^{2-} \) is paramagnetic while \( [\text{Ni}(\text{CN})_4]^{2-} \) is diamagnetic.

(i) Define molar conductance of the solution of an electrolyte and discuss its change with the concentration.
(ii) Calculate the electromotive force (EMF) of the following cell:
\( \text{Ni(s)} \mid \text{Ni}^{2+}(0.16\,M) \parallel \text{Ag}^{+}(0.002\,M) \mid \text{Ag(s)} \)
(Given: \( E^{\circ}_{cell} = 1.05\,V \), \( \log_{10}2 = 0.3010 \))

Derive the integrated rate equation for first order reaction. Show that half life period for this reaction does not depend on initial concentration of the reactants. (2+1=3)

A first order reaction takes 10 min for 20% decomposition. Calculate the time taken for the reaction to go to 80% decomposition. (Given, \( \log_{10}2 = 0.3010 \))

Explain the following in relation to proteins:
(i) Peptide bond
(ii) Denaturation

Write short notes on the following: (i) Coupling reaction (ii) Sandmeyer reaction (iii) Friedel-Craft reaction. (2+1½+1½=5)
OR
Write chemical equations for obtaining the following from benzene diazonium chloride: (i) Phenyl cyanide (ii) Bromobenzene (iii) Nitrobenzene (iv) p-hydroxyazobenzene (v) p-Aminoazobenzene. (1+1+1+1+1=5)

(i) Explain Henry's law. (ii) 200 ml of an aqueous solution of a protein contains 1.26 g of protein. The osmotic pressure of such a solution at 300 K is found to be 2.57 × 10^-3 bar. Calculate the molar mass of the protein. (1+2=3)

Write a short note on the structure of nucleic acid. (2)

Write the chemical equations when an aldehyde reacts with the following: (i) Tollen's reagent (ii) Fehling's reagent. (1+1=2)

Describe the charging and discharging mechanism of lead storage battery with the help of chemical reactions. (1½+1½=3)

Aqueous solution of sodium chloride boils at higher temperature than water, but it freezes at lower temperature than water. Explain with reason.

Define molality and molarity.

Write IUPAC names of the following coordination compounds:
(i) [PtCl₂(en)₂](NO₃)₂
(ii) [Cr(NH₃)₆][Co(CN)₆]

Explain why phenol is more acidic than ethyl alcohol.

Explain the mechanism of bimolecular nucleophilic substitution (S_N2) reaction of alkyl halide.

Mention the different steps for the preparation of potassium dichromate from iron chromite ore and draw the structure of dichromate ion.