For acrylic, a clear rigid plastic, to be cast, fairly

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For acrylic, a clear rigid plastic, to be cast, fairly complex molecules must be induced to link up, in a process called polymerization. Polymerization is exothermic; i.e., its net effect is that each time molecules link, a small quantity of heat is generated.In addition, the rate of linking speeds up as temperature increases.

Which of the following can be inferred from the passage above?

(A) The method used to trigger the process of polymerization is a sharp increase in the temperature of the surrounding air.

(B) Unless the heat that results from the linking of molecules is drawn off promptly, there will be a heat buildup at an accelerating rate as acrylic is cast.

(C) In the casting of thin sheets of acrylic, which lose heat quickly to the surrounding air, polymerization proceeds much faster than it does in the casting of thick pieces.

(D) If air temperatures are kept steady when acrylic is cast, the rate at which the molecules link remains constant.

(E) Once the process of polymerization has been induced, it cannot be slowed before all possible links among molecules have been formed.

my doubt is : how can we infer B when in fact it might be case the heat produced in the experiment is being used to fuel further reaction .also it has been said that a rise in temperature speeds up the reaction .my contention is that "drawing off heat promptly" might not be a required if in case the same heat is being used for further reaction

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by Kasia@EconomistGMAT » Tue Mar 05, 2013 6:55 am
hi Aditya,

Answer B is the best choice.It is clearly linked to the premises. We know that the once triggered reaction accelerates as the heat is produced. The fact that higher temperature is needed for the reaction does not need to be true. It is possible that the reaction only needs to be triggered and then it somehow self-generates. A speaks about a method used to trigger the reaction and we simply can't infer it based on the premises. We only know what happens once the reaction has been triggered. C again is not a proper inference that we can make based on the argument. It is not stated what the differences can be if sheets vary in thickness. Answer D is also incorrect - we know that the reaction accelerates once the temperature increases. Finally, choice E is also not a good option. We cannot infer that the reaction cannot be stopped.
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