List of top Chemistry Questions

If 0.561 g of KOH is dissolved in water to give 200 mL of solution at 298 K. Calculate the concentrations of potassium, hydrogen and hydroxyl ions. What is its pH?
The pH of milk, black coffee, tomato juice, lemon juice and egg white are 6.8, 5.0, 4.2, 2.2 and 7.8 respectively. Calculate corresponding hydrogen ion concentration in each.
The ionization constant of propanoic acid is 1.32 × 10–5. Calculate the degree of ionization of the acid in its 0.05M solution and also its pH. What will be its degree of ionization if the solution is 0.01M in HCl also?
Why is benzene extra ordinarily stable though it contains three double bonds?
Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below: 
(a) Human muscle-fluid,6.83 
(b) Human stomach fluid,1.2 
(c) Human blood,7.38 
(d) Human saliva,6.4
Write chemical equations for combustion reaction of the following hydrocarbons:
  1. Butane
  2. Pentene
  3. Hexyne
  4. Toluene
Draw the cis and trans structures of hex-2-ene. Which isomer will have higher b.p. and why?
Propanal and pentan-3-one are the ozonolysis products of an alkene? What is the structural formula of the alkene?
An alkene ‘A’ contains three C – C, eight C – H σ bonds and one C – C \(\pi\) bond. ‘A’ on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write IUPAC name of ‘A’.
An alkene 'A' on ozonolysis gives a mixture of ethanal and pentan-3-one. Write structure and IUPAC name of 'A'.
Write IUPAC names of the products obtained by the ozonolysis of the following compounds:
  1. Pent-2-ene 
  2. 3,4-Dimethyl-hept-3-ene 
  3. 2-Ethylbut-1-ene
  4. 1-Phenylbut-1-ene
For the following compounds, write structural formulas and IUPAC names for all possible isomers having the number of double or triple bond as indicated: 
  1. C4H8 (one double bond) 
  2. C5H8 (one triple bond)
The ionization constant of dimethylamine is 5.4 × 10–4. Calculate its degree of ionization in its 0.02M solution. What percentage of dimethylamine is ionized if the solution is also 0.1M in NaOH?
Calculate the degree of ionization of 0.05M acetic acid if its pKa value is 4.74. How is the degree of dissociation affected when its solution also contains (a) 0.01M (b) 0.1M in HCl ?
What is the pH of 0.001M aniline solution? The ionization constant of aniline can be taken from Table 6.7. Calculate the degree of ionization of aniline in the solution. Also calculate the ionization constant of the conjugate acid of aniline.
How will you convert benzene into 
  1. p-nitrobromobenzene
  2. m-nitrochlorobenzene 
  3. p -nitrotoluene
  4. acetophenone
The pH of 0.005M codeine (C18H21NO3) solution is 9.95. Calculate its ionization constant and pKb.
The degree of ionization of a 0.1M bromoacetic acid solution is 0.132. Calculate the pH of the solution and the pKa of bromoacetic acid.
Suggest the name of a Lewis acid other than anhydrous aluminium chloride which can be used during ethylation of benzene.
Out of benzene, m-dinitrobenzene and toluene which will undergo nitration most easily and why?
Arrange the following set of compounds in order of their decreasing relative reactivity with an electrophile, E+
  1. Chlorobenzene, 2,4-dinitrochlorobenzene, p-nitrochlorobenzene 
  2. Toluene, p-H3C-C6H4-NO2, p-O2N-C6H4-NO2.
Write structures of all the alkenes which on hydrogenation give 2-methylbutane.
How would you convert the following compounds into benzene? 
  1. Ethyne
  2. Ethene
  3. Hexane
Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?
Write down the products of ozonolysis of 1,2-dimethylbenzene (o-xylene). How does the result support Kekulé structure for benzene?