1
JEE Main 2021 (Online) 27th August Evening Shift
Numerical
+4
-1
Change Language
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)
Your input ____
2
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The angle between the straight lines, whose direction cosines are given by the equations 2l + 2m $$-$$ n = 0 and mn + nl + lm = 0, is :
A
$${\pi \over 2}$$
B
$$\pi - {\cos ^{ - 1}}\left( {{4 \over 9}} \right)$$
C
$${\cos ^{ - 1}}\left( {{8 \over 9}} \right)$$
D
$${\pi \over 3}$$
3
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Let $$A = \left( {\matrix{ {[x + 1]} & {[x + 2]} & {[x + 3]} \cr {[x]} & {[x + 3]} & {[x + 3]} \cr {[x]} & {[x + 2]} & {[x + 4]} \cr } } \right)$$, where [t] denotes the greatest integer less than or equal to t. If det(A) = 192, then the set of values of x is the interval :
A
[68, 69)
B
[62, 63)
C
[65, 66)
D
[60, 61)
4
JEE Main 2021 (Online) 27th August Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Let M and m respectively be the maximum and minimum values of the function
f(x) = tan$$-$$1 (sin x + cos x) in $$\left[ {0,{\pi \over 2}} \right]$$, then the value of tan(M $$-$$ m) is equal to :
A
$$2 + \sqrt 3 $$
B
$$2 - \sqrt 3 $$
C
$$3 + 2\sqrt 2 $$
D
$$3 - 2\sqrt 2 $$
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