Problem 24
Explain the principle of paper chromatography.
Problem 25
Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?
Problem 26
Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.
Problem 27
Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.
Problem 28
Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation?
Problem 29
Will \(\mathrm{CCl}_{4}\) give white precipitate of \(\mathrm{AgCl}\) on heating it with silver nitrate? Give reason for your answer.
Problem 30
Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the estimation of carbon present in an organic compound?
Problem 32
An organic compound contains \(69 \%\) carbon and \(4.8 \%\) hydrogen, the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when \(0.20 \mathrm{~g}\) of this substance is subjected to complete combustion.
Problem 33
A sample of \(0.50 \mathrm{~g}\) of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in \(50 \mathrm{ml}\) of \(0.5 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}\). The residual acid required \(60 \mathrm{~mL}\) of \(0.5 \mathrm{M}\) solution of \(\mathrm{NaOH}\) for neutralisation. Find the percentage composition of nitrogen in the compound.
Problem 34
\(0.3780 \mathrm{~g}\) of an organic chloro compound gave \(0.5740 \mathrm{~g}\) of silver chloride in Carius estimation. Calculate the percentage of chlorine present in the compound.
