List of top Chemistry Questions

In RNA, thymine is replaced by__________.
The unit cell length of sodium chloride crystal is 564 pm. Its density would be:

Discuss briefly giving an example in each case the role of coordination compounds in:

  1. biological systems
  2. medicinal chemistry
  3. analytical chemistry
  4. extraction/ metallurgy of metals
1.5 mol of $O_2$ combine with Mg to form oxide MgO. The mass of Mg (at. mass 24) that has combined is
Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of H2 gas at the cathode is: (1 Faraday =96500Cmol−1)
The correct order of ionisation enthalpy for Li, Na, Cl, F is:
The letter ?$D$? in $D$-carbohydrates represents
Complexes formed in the cyanide process are:
A solution of colourless unknown salt (X) on boiling with excess of NaOH produces non-flammable gas. The gas evolution ceases after some time. Upon addition of Zn dust to the same solution, the gas evolution restarts. The colourless salt (X) is (are)
The vapour pressure of water at room temperature is 23.8 mm Hg. The vapour pressure of an aqueous solution of sucrose with mole fraction 0.1 is equal to

Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction. 
\((i) Methanal \)
\((ii) 2-Methylpentanal \)
\((iii) Benzaldehyde \)
\((iv) Benzophenone \)
\((v) Cyclohexanone \)
\((vi) 1-Phenylpropanone \)
\((vii) Phenylacetaldehyde \)
\((viii) Butan-1-ol \)
\((ix) 2, 2-Dimethylbutanal\)

The longest wavelength in Ao in the Balmer series of singly ionised helium ion, He+ is

Indicate the steps in the preparation of: 

  1.  K2Cr2O7 from chromite ore. 
  2.  KMnO4 from pyrolusite ore.
In which of the following molecules, is the covalent bond most polar ?
Consider the following reaction in aqueous medium at 25oC.
The equilibrium of above reaction shifts towards left in the presence of
3-tert-butylphenol reacts with different halogens by electrophillic substitution under appropriate conditions that are given below:
The observed pattern of electrophillic substitution can be explained by
Which law directly explains the law of conservation of mass ?
Electrovalent bond formation depends on
The melting point of particles in nano form ___________
Taking chromium and arsenic, which are toxic, out of pressure-treated wood, and using new less toxic chemicals for bleaching paper, are examples of___________.
Solid Ba(NO3)2 is gradually dissolved in a 1.0×10−4MNa2CO3 solution. At which concentration of Ba2+, precipitate of BaCO3 begins to form?(Ksp for BaCO3=5.1×10−9)
When 10ml of 0.2M solution of an acid is added to 250ml of a buffer solution with pH=6.34, the pH of the solution becomes 6.32. The buffer capacity of the solution is:
The tendency of a reaction to take place spontaneously is greatest when the reaction is:
In the presence of a catalyst, the heat evolved or absorbed during the reaction _______.
Given the solubility curves of KNO3 and KCl, which of the following statements is not true?