List of top Chemistry Questions

Will CCl4 give white precipitate of AgCl on heating it with silver nitrate? Give reason for your answer.
Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation ?
Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.
Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?
Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.
Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?
Write Lewis symbols for the following atoms and ions: \(S\) and \(S ^{2-}\) ; \(Al\) and \(Al ^{3+}\) ; \(H\) and \(H ^-\)
Discuss the principle of estimation of halogens, sulphur and phosphorus present in an organic compound.
The following data are obtained when dinitrogen and dioxygen react together to form different compounds: 
          Mass of dinitrogen                Mass of dioxygen 
(i)              14 g                                            16 g 
(ii)             14 g                                             32 g 
(iii)            28 g                                             32 g 
(iv)            28 g                                             80 g 
  1. Which law of chemical combination is obeyed by the above experimental data? Give its statement.
  2. Fill in the blanks in the following conversions: 
    (i)1 km = ...................... mm = ...................... pm 
    (ii) 1 mg = ...................... kg = ...................... ng 
    (iii) 1 mL = ...................... L = ...................... dm3
How will you bring about the following conversions?
  1. Ethanol to but-1-yne
  2. Ethane to bromoethene
  3. Propene to 1-nitropropane
  4. Toluene to benzyl alcohol
  5. Propene to propyne
  6. Ethanol to ethyl fluoride
  7. Bromomethane to propanone
  8. But-1-ene to but-2-ene
  9. 1-Chlorobutane to n-octane
  10. Benzene to biphenyl.
A sample of drinking water was found to be severely contaminated with chloroform, CHCl3, supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
  1. Express this in per cent by mass.
  2. Determine the molality of chloroform in the water sample.
What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final volume up to 2L?
What is the difference between distillation, distillation under reduced pressure and steam distillation?
Describe the method, which can be used to separate two compounds with different solubilities in a solvent S.
Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles. 
(a) \(CH_3COOH+HO^{–6} \rightarrow CH_3COO^–+H_2O\) 
(b) \(CH_3COCH^{3+} C^–N\rightarrow (CH_3)_2C(CN)(OH)\)
(c) \(C_6H_6 + CH_3C+O^+ \rightarrow C_6H_5COCH_3\)
Calculate the concentration of nitric acid in moles per litre in a sample which has a density, 1.41 g mL–1 and the mass per cent of nitric acid in it being 69%.
What are electrophiles and nucleophiles? Explain with examples.
Which of the two, \(O+2NCH_2CH_2O^- \,or \,CH_3CH_2O^–\)is expected to be more stable and why?
Identify the substance oxidised, reduced, oxidising agent and reducing agent for each of the following reactions:
  1. \(2AgBr (s) + C_6H_6O_2(aq) \rightarrow 2Ag(s) + 2HBr (aq) + C_6H_4O_2(aq)\)
  2. \(HCHO(l) + 2[Ag (NH_3)_2] ^+ (aq) + 3OH^ - (aq) \rightarrow 2Ag(s) + HCOO ^- (aq) + 4NH_3(aq) + 2H_2O(l)\)
  3. \(HCHO (l) + 2Cu^{ 2+}(aq) + 5 OH^ - (aq) \rightarrow Cu_2O(s) + HCOO ^- (aq) + 3H_2O(l)\)
  4. \(N_2H_4(l) + 2H_2O_2(l) \rightarrow N_2(g) + 4H_2O(l)\)
  5. \(Pb(s) + PbO_2(s) + 2H_2SO_4(aq) \rightarrow  2PbSO_4(s) + 2H_2O(l)\)
Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm. Calculate the frequency (ν) and wavenumber (v) of the yellow light
Give the IUPAC names of the following compounds:
IUPAC names of compounds
(f) Cl2CHCH2OH
An ion with mass number 37 possesses one unit of negative charge. If the ion conatins 11.1% more neutrons than the electrons, find the symbol of the ion.
Calculate the oxidation number of Sulphur, chromium, and nitrogen in
\(H_2SO_5\), \(Cr_2O_7^{2−}\) and \(NO_3^−\). Suggest structure of these compounds. Count for the fallacy.
Write bond line formulas for, Isopropyl alcohol, 2,3-Dimethylbutanal, Heptan-4-one.
Indicate the σ and π bonds in the following molecules. \(C_6H_6, C_6H_{12}, CH_2Cl_2, CH_2=C=CH_2, CH3NO2, HCONHCH_3.\)