1
JEE Main 2021 (Online) 27th August Evening Shift
Numerical
+4
-1
Two flasks I and II shown below are connected by a valve of negligible volume.

When the valve is opened, the final pressure of the system in bar is x $$\times$$ 10$$-$$2. The value of x is __________. (Integer answer)

[Assume - Ideal gas; 1 bar = 105 Pa; Molar mass of N2 = 28.0 g mol$$-$$1; R = 8.31 J mol$$-$$1 K$$-$$1]
2
JEE Main 2021 (Online) 27th August Evening Shift
Numerical
+4
-1
Data given for the following reaction is as follows :

FeO(s) + C(graphite) $$\to$$ Fe(s) + CO(g)

Substance $$\Delta H^\circ$$
(kJ mol$$^{ - 1}$$)
$$\Delta S^\circ$$
(J mol$$^{ - 1}$$ K$$^{ - 1}$$)
$$Fe{O_{(s)}}$$ $$- 266.3$$ 57.49
$${C_{(graphite)}}$$ 0 5.74
$$F{e_{(s)}}$$ 0 27.28
$$C{O_{(g)}}$$ $$- 110.5$$ 197.6

The minimum temperature in K at which the reaction becomes spontaneous is ___________. (Integer answer)
3
JEE Main 2021 (Online) 27th August Morning Shift
Numerical
+4
-1
200 mL of 0.2 M HCl is mixed with 300 mL of 0.1 M NaOH. The molar heat of neutralization of this reaction is $$-$$57.1 kJ. The increase in temperature in $$^\circ$$C of the system on mixing is x $$\times$$ 10$$-$$2. The value of x is ___________. (Nearest integer)

[Given : Specific heat of water = 4.18 J g$$-$$1 K$$-$$1, Density of water = 1.00 g cm$$-$$3]

[Assume no volume change on mixing)
4
JEE Main 2021 (Online) 26th August Evening Shift
Numerical
+4
-1
For water $$\Delta$$vap H = 41 kJ mol$$-$$1 at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is ___________ kJ mol$$-$$1

[Use : R = 8.3 J mol$$-$$1 K$$-$$1]