CBSE Class 12 Chemistry - Aldehydes, Ketones And Carboxylic Acids VBQs Based on CBSE and NCERT guidelines. Value based questions are now being given in exams to promote morals and values in students, Students should read and understand the following VBQs to get better understanding and score good marks in exams
ALDEHYDES, KETONES AND CARBOXYLIC ACIDS
1. The term “Green chemistry” as adopted by the IUPAC working pastly on synthetic pathways and processes in green chemistry is getting awareness even among common people. My mother who has retired twenty years ago, as working with a laboratory synthesizing aldehydes using.
RCOCl + H2 RCHO + HCl
Myself, working in the same lab adopted this method but my mother advised not to use this method and suggested another one Now
answer the following questions:
(i)Why did my mother advise not to use given method
(ii) What was another method? Did you consider it to be environmental friendly and economically?
Answers) (i) BaSO4 causes toxic problems. My mother having recent knowledge about green chemistry advised me to discard this method.
(ii) Another method does not use BaSO4
2. Formaldehyde (Methanal) is gas at room temperature. It is soluble in water because it is polar. It has pungent smell.
I. What is formalin? Give its use.
II. Which thermoplastics can be made from formalin? Give their uses also.
III. Name a medicine prepared from formaldehyde? Give chemical equation and its use.
IV. What is the problem in using formalin?
Solution: i) 40% aqueous solution of formaldehyde is called Formalin.
ii) a) Urea – Formaldehyde resin: It is used for making unbreakable crockery.
b) Phenol – Formaldehyde resin (Bakelite): It is used for making electrical switches and switch boards.
iii) It is used for the preparation of Urotropine ( urinary antiseptic)
iv) It is strongly pungent smelling, which is difficult
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