Thermodynamics Question 102
Question: Following reaction occurring in an automobile $ 2C _{8}H _{18}(g)+25O _{2}(g)\to 16CO _{2}(g)+18H _{2}O(g). $ The sign of $ \Delta H,\Delta S $ and $ \Delta G $ would be
[CBSE PMT 1994; KCET 1999]
Options:
A) +, -, +
B) -, +, -
C) -, +, +
D) +, +, -
Show Answer
Answer:
Correct Answer: B
Solution:
For Combustion reaction, $ \Delta H $ is negative, $ \Delta n=(16+18)-(25+2)=+7 $ , so $ \Delta S $ is $ +ve $ , reaction is spontaneous, hence $ \Delta G $ is -ve.
