1
JEE Main 2021 (Online) 24th February Evening Shift
Numerical
+4
-1
Assuming ideal behaviour, the magnitude of log K for the following reaction at 25$$^\circ$$C is x $$\times$$ 10$$-$$1. The value of x is ______________. (Integer answer)

$$3HC \equiv C{H_{(g)}} \rightleftharpoons {C_6}{H_{6(l)}}$$

[Given : $${\Delta _f}{G^o}(HC \equiv CH) = - 2.04 \times {10^5}$$ J mol$$-$$1 ; $${\Delta _f}{G^o}({C_6}{H_6}) = - 1.24 \times {10^5}$$ J mol$$-$$1 ; R = 8.314 J K-1 mol$$-$$1]
2
JEE Main 2020 (Online) 5th September Evening Slot
Numerical
+4
-0
For a dimerization reaction,
2A(g) $$\to$$ A2(g)
at 298 K, $$\Delta$$Uo = –20 kJ mol–1, $$\Delta$$So = –30 JK–1 mol–1,
then the $$\Delta$$Go will be _____ J.
3
JEE Main 2020 (Online) 2nd September Evening Slot
Numerical
+4
-0
The heat of combustion of ethanol into carbon dioxide and water is – 327 kcal at constant pressure. The heat evolved (in cal) at constant volume and 27oC (if all gases behave ideally) is (R = 2 cal mol–1 K–1) ________.
4
JEE Main 2020 (Online) 2nd September Morning Slot
Numerical
+4
-0
The internal energy change (in J) When 90 g of water undergoes complete evaporation at 100oC is ____________.

(Given : $$\Delta$$Hvap for water at 373 K = 41 kJ/mol,
R = 8.314 JK–1 mol–1)