List of top Questions asked in UP Board XII

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.
What do you mean by D and L configurations of carbohydrates? Draw the structural formula of D-Glucose and D-Fructose.
Write a short note on Coagulation.
‘Action of soap is based on the emulsification and micelle formation.’ Comment on it.
Zn$^{2+}$ salts are colourless while Ni$^{2+}$ salts are coloured. Why?
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 Osmotic pressure. How will you show that Osmotic pressure is a colligative property?
Write a short note on primary and secondary structures of proteins.
Define Lyophilic and Lyophobic colloids with examples. Why is Lyophobic colloids easily coagulated?
$H_2O$ is a liquid while $H_2S$ is a gas. Why?
Hinsberg’s reagent is –
The crystal system having dimensions $a \neq b \neq c$ and $\alpha = \beta = \gamma = 90^\circ$ is:
What is Schottky defect? What is the effect of the presence of Schottky defect on the density of lattice?
The unit of velocity constant for first order reactions is:
The concentration unit independent of temperature is:
Which of the following base is not present in DNA?
Benzyl alcohol is obtained from benzaldehyde by –
Write short notes on the following: (i) Reimer–Tiemann reaction
(ii) Kolbe reaction
Write a short note on Nucleophilic substitution reactions in haloalkanes.
How will you obtain the following from Chlorobenzene? (Write only chemical equations) (i) Picric Acid
(ii) Dichlorobenzene
(iii) Chlorobenzene Sulphonic Acid
Write chemical equations of two methods of preparation of monohydric alcohol and also write chemical equation of the reactions of ethyl alcohol with conc. sulphuric acid (H$_2$SO$_4$) at different temperatures.
Write chemical equation for the preparation of ozone and its three oxidizing properties.
What is Aqua Regia? What happens when aqua regia reacts with (i) Gold, and (ii) Platinum.