List of top Chemistry Questions asked in UP Board XII

Write the names of two lyophilic and two lyophobic colloids.
Gas present in food packet of substances is:
Structure of the crystal of sodium chloride is:
Molecular formula of sulphur at ordinary temperature is:
The charge on colloidal particles of Fe\(_2\)O\(_3 \cdot xH_2O\) is:
Describe Ostwald’s process for the industrial manufacture of nitric acid. Write the balanced chemical equations of the following reactions: (i) Zinc metal reacts with conc. HNO$_3$
(ii) Iodine reacts with conc. HNO$_3$
What happens when Sulphur dioxide reacts with acidic potassium permanganate? Write balanced chemical equation for this reaction.
Give reason that bleaching action of chlorine is permanent while that of SO$_2$ is temporary.
Discuss the mechanism of unimolecular and bimolecular nucleophilic substitution reactions in haloalkanes.
Explain why NH$_3$ is basic in nature.
Write the mechanism of dehydration of ethanol.
Write short notes on the following: (A) Reimer–Tiemann Reaction
(B) Kolbe’s Reaction
(C) Williamson Ether Synthesis
Explain Werner’s postulates related to the bonding in coordination compounds.
What do you mean by D and L configurations of carbohydrates? Draw the structural formula of D-Glucose and D-Fructose.
Zn$^{2+}$ salts are colourless while Ni$^{2+}$ salts are coloured. Why?
Write a short note on Gabriel’s phthalimide synthesis. Why is Gabriel’s phthalimide synthesis preferred for synthesizing the primary amines?
What is half-life for a chemical reaction? Show that the half-life for a first order reaction is independent of the initial concentration of the reactants.
Write a short note on Coagulation.
‘Action of soap is based on the emulsification and micelle formation.’ Comment on it.
Write a short note on primary and secondary structures of proteins.
$H_2O$ is a liquid while $H_2S$ is a gas. Why?
Define Osmotic pressure. How will you show that Osmotic pressure is a colligative property?
Calculate the packing efficiency of body centred cubic (b.c.c.) unit cell.
Explain Kohlrausch’s law of independent migration of ions. Mention one application of this law.
Define Lyophilic and Lyophobic colloids with examples. Why is Lyophobic colloids easily coagulated?