CBSE Class 12 Chemistry Worksheet - Ethers. CBSE issues sample papers every year for students for class 12 board exams. Students should solve the CBSE issued sample papers to understand the pattern of the question paper which will come in class 12 board exams this year. The sample papers have been provided with marking scheme. It’s always recommended to practice as many CBSE sample papers as possible before the board examinations. Sample papers should be always practiced in examination condition at home or school and the student should show the answers to teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.
Q1. Give reasons for the following;-
(a) The c-o-c bond angle in ethers is larger than the tetrahedral value.
(b) Ethers are miscible in water just as alcohol’s are
(c) Boiling pts. Of ethers are comparable to those of ethers of comparable molecular mass.
(d) Ethers have a net dipole moment even if they are symmetrical in structure.
(e) For the preparation of t-butyl methyl ethers, methyl bromide and sodium t-butoxide is used. Reaction of sodium methoxide and t-butyl bromide can’t be used.
(f) Acid catalysed formation of ethers from alcohols is not appropriate for preparation of unsymmetrical ethers.
(g) Anisole is prepared by reacting sodium phenoxide with methyl bromide and not bromobenzene and sodium methoxide.
(h) When alkyl aryl ethers are cleaved with halogen acid, the yield is phenol and a molecule of alkyl halide and not phenyl halide and alcohol.
(i) When ethers with 10 and 20 alkyl groups are cleaved with excess of HI under drastic conditions, alkyl iodide is formed with lower alkyl group.
(j) When tert-butyl methyl ether is hydrolysed with HI under drastic conditions, the products are methanol and t-butyl iodide and not butyl alcohol and methyl iodide.
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