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Organic Chemistry – Some Basic Principles And Techniques

Question
CBSEENCH11007624
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Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract for testing sulphur by lead acetate test? 

Solution

When sodium extract is acidified with acetic acid and lead acetate is added to it, a black precipitate of lead sulphide is formed.
straight S to the power of negative 2 end exponent space plus space Pb to the power of 2 plus end exponent space space rightwards arrow space space space PbS
PbS is insoluble in acetic acid and soluble in sulphuric acid.Also,because SO42- ions from H2SO4 reacts with Pb++ from Lead Acetate, giving a White ppt of PbSO4, though sulphur is not present in the organic compound.
straight H subscript 2 SO subscript 4 rightwards harpoon over leftwards harpoon space 2 straight H to the power of plus space plus SO subscript 4 superscript 2 minus end superscript Pb to the power of 2 plus end exponent space plus SO subscript 4 superscript 2 minus end superscript space rightwards harpoon over leftwards harpoon PbSO subscript 4

Some More Questions From Organic Chemistry – Some Basic Principles and Techniques Chapter

What type of hybridisation is involved in: (i) Planar (ii) Linear molecules?

What does IUPAC stand for?

What system of nomenclature is accepted universally?

What are isomers?

How many chain isomers are possible for pentane?

Which characteristic is common to different isomers of a compound?

 

Name three alkanes which do not show chain isomerism.

Name the types of structural isomerism shown by alkanes.

Name the four main types of structural isomerism. 

Write the three possible open chains of five carbon atoms

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