JEE Main On 16 April 2018 Question 29
Question: For which of the following processes, $ \Delta S $ is negative? [JEE Main 16-4-2018]
Options:
A) $ N _2(g,273K)\to N _2(g,300K) $
B) $ N _2(g,1atm)\to N _2(g,5atm) $
C) $ C(diamond)\to C(graphite) $
D) $ H _2(g)\to 2H(g) $
Show Answer
Answer:
Correct Answer: B
Solution:
- A. When we increase the temperature of a gas then randomness is increased due to kinetic energy gained by molecules. So, $ \Delta S>0 $ B. When pressure increases then molecules of gas will come closer and intermolecular distance decreases so entropy will also decrease. and $ \Delta S<0 $ C. When Diamond is converted into graphite when it is heated to $ 1500{{,}^{o}}C $ and entropy is increased so $ \Delta S>0 $ D. $ H _2 $ molecule is converted into atoms, So entropy will increase. So $ \Delta S>0 $
