Answer
Verified
91.5k+ views
Hint: There are different classes of polymers. Novolac is a phenolic resin type of polymer. It is extensively used in microelectronics.
Complete step by step answer: A polymer is a large molecule formed by continuous linking of many small subunits called Monomers. Basically, it is a repetition of monomers.
Another name for novolac is phenolic resin or phenol formaldehyde resin. As this suggests, the two monomers needed to form novolac are phenol and formaldehyde.
The reaction that occurs is –
The reaction stops when the formaldehyde reactant is exhausted, often leaving up to 10% of un-reacted phenol.
So, B is the correct option.
Additional information: There are two types of polymers, natural and artificial. Natural polymers are found in plants. Apart from natural and manmade, polymers are classified in various other ways.
Based on the type of monomer used and mechanism of polymerization, there are different types of polymers. Novolac is a cross linked polymer formed by condensation polymerisation. During preparation of novolac, as a general rule phenol gets substituted on both ortho and para positions. But we know that para position is almost twice as reactive as ortho. But there are twice as many ortho sites (two per phenol molecule) so the fractions of ortho-ortho, para-para and ortho-para bridges are approximately equal. In this reaction, a water molecule gets eliminated. Hence the type of polymerization mechanism is condensation. Distillation of the molten resin during manufacturing removes the excess phenol and water.
Note: To remember this easily, we can keep in mind that novolac is a phenolic resin type of polymer. It has a cross linked structure and is formed by condensation polymerization.
Complete step by step answer: A polymer is a large molecule formed by continuous linking of many small subunits called Monomers. Basically, it is a repetition of monomers.
Another name for novolac is phenolic resin or phenol formaldehyde resin. As this suggests, the two monomers needed to form novolac are phenol and formaldehyde.
The reaction that occurs is –
The reaction stops when the formaldehyde reactant is exhausted, often leaving up to 10% of un-reacted phenol.
So, B is the correct option.
Additional information: There are two types of polymers, natural and artificial. Natural polymers are found in plants. Apart from natural and manmade, polymers are classified in various other ways.
Based on the type of monomer used and mechanism of polymerization, there are different types of polymers. Novolac is a cross linked polymer formed by condensation polymerisation. During preparation of novolac, as a general rule phenol gets substituted on both ortho and para positions. But we know that para position is almost twice as reactive as ortho. But there are twice as many ortho sites (two per phenol molecule) so the fractions of ortho-ortho, para-para and ortho-para bridges are approximately equal. In this reaction, a water molecule gets eliminated. Hence the type of polymerization mechanism is condensation. Distillation of the molten resin during manufacturing removes the excess phenol and water.
Note: To remember this easily, we can keep in mind that novolac is a phenolic resin type of polymer. It has a cross linked structure and is formed by condensation polymerization.
Recently Updated Pages
Name the scale on which the destructive energy of an class 11 physics JEE_Main
Write an article on the need and importance of sports class 10 english JEE_Main
Choose the exact meaning of the given idiomphrase The class 9 english JEE_Main
Choose the one which best expresses the meaning of class 9 english JEE_Main
What does a hydrometer consist of A A cylindrical stem class 9 physics JEE_Main
A motorcyclist of mass m is to negotiate a curve of class 9 physics JEE_Main
Other Pages
3 mole of gas X and 2 moles of gas Y enters from the class 11 physics JEE_Main
If the central portion of a convex lens is wrapped class 12 physics JEE_Main
A 60g bullet is fired through a stack of fiberboard class 11 physics JEE_Main
Electric field due to uniformly charged sphere class 12 physics JEE_Main
Derive an expression for maximum speed of a car on class 11 physics JEE_Main
If the frequency of Kalpha X rays emitted from the class 12 physics JEE_Main