Medium MCQ +4 / -1 PYQ · JEE Mains 2021

Given below are two statements. One is labelled as Assertion A nd the other is labelled as Reason R.

Assertion A : Sharp glass edge becomes smooth on heating it upto its melting point.

Reason R : The viscosity of glass decreases on melting.

Choose the most appropriate answer from the options given below.

  1. A A is true but R is false
  2. B Both A and R are true but R is NOT the correct explanation of A. Correct answer
  3. C A is false but R is true.
  4. D Both A and R are true and R is the correct explanation of A.

Solution

<p>On heating the glass, it melts and takes up rounded shape at the edges, which has minimum surface area. This is due to the property of surface tension of liquids and not due to decrease in viscosity.</p> <p>Viscosity generally decreases as the temperature increases.</p> <p>Hence, both A and R are true but R is not the correct explanation of A.</p>

About this question

Subject: Chemistry · Chapter: States of Matter · Topic: Gas Laws

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