List of top Chemistry Questions asked in UP Board XII

(i) Explain Kohlrausch's law. Write its applications.

Explain Lanthanide contraction with reason.

Zn\(^{2+}\) salts are white while Cu\(^{2+}\) salts are blue in colour. Why?

Calculate the e.m.f. of the following cell: \[ \text{Cu(s)} | \text{Cu}^{2+} (1M) || \text{Ag}^{+} (0.01M) | \text{Ag(s)} \] Given: \[ E^0_{\text{Cu}^{2+}/\text{Cu}} = +0.34V, \quad E^0_{\text{Ag}^{+}/\text{Ag}} = +0.80V \]

Explain ionisation isomerism and coordination isomerism in coordination compounds with examples.

Write the main sources and the diseases caused by the deficiency of vitamins A and C.

Explain by giving the example of chlorobenzene that chlorine is ortho- and para-directing in electrophilic aromatic substitution reactions.

 Write I.U.P.A.C. names of the following coordination compounds:

(i) Write the cell reactions taking place during the discharge of the lead storage battery.

What is Tollen's reagent? Write the chemical equation of the reaction of aldehyde with Tollen's reagent.

Discuss Werner's theory of coordination compounds.

Which of the following is obtained by Rosenmund's reduction of acyl chloride?
 

How is benzene diazonium chloride prepared from aniline? How will you convert benzene diazonium chloride into the following?

(b) Write short notes on the following:

(i) Preparation of ethanol from fermentation of sugar

(ii) Reimer-Tiemann Reaction

(iii) Williamson’s Synthesis

OR

(b) (i) Write chemical equations for the preparation of primary, secondary, and tertiary alcohols from Grignard’s reagent.

Primary Alcohol:

Secondary Alcohol:

Tertiary Alcohol:

(a) Explain the resonance effect in nucleophilic substitution reactions of haloarenes. By giving the example of chlorobenzene, write short notes on the following:

  • (i) Wurtz-Fittig reaction
  • (ii) Friedel-Crafts reaction

OR

(a) What happens when – (write chemical equations only)?

  • (i) Ethyl bromide reacts with sodium ethoxide?
  • (ii) Ethyl chloride reacts with alcoholic KCN?
  • (iii) Chlorobenzene reacts with nitric acid?
  • (iv) n-butyl chloride reacts with alcoholic KOH?
  • (v) Ethyl bromide reacts with magnesium metal in the presence of dry ether?

Write short notes on the following: Cannizzaro's reaction

Describe the primary and secondary structures of proteins.
What are nucleic acids? Discuss the structure of DNA with a diagram.
\([Cr(NH_3)_6]^{3+}\) is paramagnetic while \([Ni(CN)_4]^{2+}\) is diamagnetic. Explain on the basis of valence bond theory.
Calculate the e.m.f. of the following cell: \[ \text{Mg(s)} | \text{Mg}^{2+} (0.1 M) || \text{Cu}^{2+} (0.001 M) | \text{Cu(s)} \] Given: \[ E^0_{\text{Cu}^{2+}/\text{Cu}} = +0.34V, \quad E^0_{\text{Mg}^{2+}/\text{Mg}} = -2.37V \]

What are fuel cells? State Two advantages of hydrogen-oxygen fuel cell over ordinary cell.

Write a short note on the paramagnetic behaviour and formation of coloured ions of transition elements.
Why is \( La(OH)_3 \) a stronger base than \( Lu(OH)_3 \)?
Define molecularity and order of a reaction. Derive the integrated rate equation for the rate constant of first-order reaction.

Explain the difference between an electrochemical cell and electrolytic cell. State Kohlrausch's law and write its applications.