List of top Chemistry Questions asked in UP Board XII

Write chemical equations of the method of preparation of diazonium salt and its four chemical reactions.
The velocity constants of a reaction are 0.02 s\(^{-1}\) and 0.07 s\(^{-1}\) at 500 K and 700 K, respectively. Calculate the value of \( E_a \).
Write chemical equations for halogenation, nitration, and Friedel-Crafts reaction of chlorobenzene.
Define enzyme and write its mechanism.
Write chemical equation for obtaining primary, secondary, and tertiary alcohols with the help of Grignard's reagent.
Find the value of \( E^\circ_{\text{Ce}^{4+}/\text{Ce}^{3+}} \) for the reaction: \[ 2\text{Ce}^{4+} + \text{Co} \rightarrow 2\text{Ce}^{3+} + \text{Co}^{2+} \] Given: \[ E^\circ_{\text{cell}} = 1.89V, \quad E^\circ_{\text{Co}^{2+}/\text{Co}} = -0.28V \]
Explain mole fraction by an example.
Differentiate between order of chemical reaction and molecularity by giving an example.
Write the general electronic configuration of inner transition elements.
The unit of velocity constant for a first-order reaction is:
The increasing order of reducing ability of metals X, Y, and Z, given their reduction electrode potentials:
\( E^\circ_X = +0.52V, \quad E^\circ_Y = -3.03V, \quad E^\circ_Z = -1.18V \)
Write resonating structures of arylamines. Explain why arylamines exhibit basic properties. Write chemical equations of the reaction of preparation of amine from nitro and nitrile compounds.
Write chemical equations of the reactions of five methods of preparation of aldehyde.
Write short notes on the following:
Explain the reason for depression in vapour pressure. At any temperature, the vapour pressure of pure solvent is 0.745 bar. \( 0.5 \, \text{g} \) non-volatile solute was dissolved in \( 39.0 \, \text{g} \) solvent (molar mass \( 78 \, \text{g mol}^{-1} \)). The vapour pressure of the solution so obtained is 0.740 bar. Find out the molar mass of the solid.
Explain first-order reaction. The value of velocity (rate) constant \( k \) for a first-order reaction is \( 5 \times 10^{-14} \, \text{s}^{-1} \). Calculate the half-life period of the reaction.
Differentiate between elimination and substitution reactions in haloalkanes by an example.
Write chemical equations of the following reactions:
Write a short note on RNA.
Explain the mechanism of electrophilic substitution in haloarenes with the help of an example.
Explain Valence Bond Theory (VBT) in coordination compounds.
Is oxidation of bromide ion into bromine by ferric ion possible?
The boiling point of alcohols increases with the increase in the number of carbon atoms but decreases on branching. Why?
Write structural formula of primary, secondary, and tertiary benzylic alcohol.
Why does the +3 and +4 oxidation state of Cerium (Ce) remain stable?