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JEE Main 2021 (Online) 16th March Evening Shift
Numerical
+4
-1
At 25$$^\circ$$C, 50 g of iron reacts with HCl to form FeCl2. The evolved hydrogen gas expands against a constant pressure of 1 bar. The work done by the gas during this expansion is _________ J. (Round off to the Nearest Integer).

[Given : R = 8.314 J mol$$-$$1 K$$-$$1. Assume, hydrogen is an ideal gas] [Atomic mass of Fe is 55.85 u]
2
JEE Main 2021 (Online) 26th February Evening Shift
Numerical
+4
-1
The average S-F bond energy in kJ mol$$-$$1 of SF6 is __________. (Rounded off to the nearest integer)

[Given : The values of standard enthalpy of formation of SF6(g), S(g) and F(g) are - 1100, 275 and 80 kJ mol$$-$$1 respectively.]
3
JEE Main 2021 (Online) 26th February Morning Shift
Numerical
+4
-1
For a chemical reaction A + B ⇌ C + D

($${\Delta _r}{H^\Theta }$$ = 80 kJ mol$$-$$1) the entropy change $${\Delta _r}{S^\Theta }$$ depends on the temperature T (in K) as $${\Delta _r}{S^\Theta }$$ = 2T (J K$$-$$1mol$$-$$1).

Minimum temperature at which it will become spontaneous is ___________ K. (Integer)
An exothermic reaction X $$\to$$ Y has an activation energy 30 kJ mol$$-$$1. If energy change $$\Delta$$E during the reaction is $$-$$20 kJ, then the activation energy for the reverse reaction in kJ is ___________. (Integer answer)