1
JEE Main 2021 (Online) 26th August Evening Shift
+4
-1
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : Photochemical smog causes cracking of rubber.

Reason (R) : Presence of ozone, nitric oxide, acrolein, formaldehyde and peroxyacetyl nitrate in photochemical smog makes it oxidizing.

Choose the most appropriate answer from the options given below :
A
Both (A) and (R) are true but (R) is not the true explanation of (A)
B
(A) is false but (R) is true.
C
(A) is true but (R) is false.
D
Both (A) and (R) are true and (R) is the true explanation of (A)
2
JEE Main 2021 (Online) 26th August Morning Shift
+4
-1
The conversion of hydroxyapatite occurs due to presence of F$$-$$ ions in water. The correct formula of hydroxyapatite is :
A
[3Ca3(PO4)2 . Ca(OH)2]
B
[3Ca(OH)2 . CaF2]
C
[Ca3(PO4)2 . CaF2]
D
[3Ca3(PO4)2 . CaF2]
3
JEE Main 2021 (Online) 27th July Morning Shift
+4
-1
Which one of the following statements is NOT correct?
A
Eutrophication indicates that water body is polluted
B
The dissolved oxygen concentration below 6 ppm inhibits fish growth
C
Eutrophication leads to increase in the oxygen level in water
D
4
JEE Main 2021 (Online) 25th July Evening Shift
+4
-1
Given below are two statements :

Statement I : Chlorofluoro breakdown by radiation in the visible energy region and release chlorine gas in the atmosphere which then reacts with stratospheric ozone.

Statement II : Atmospheric ozone reacts with nitric oxide to give nitrogen and oxygen gases, which add to the atmosphere.

For the above statements choose the correct answer from the options given below :
A
Statement I is incorrect but Statement II is true
B
Both Statement I and II are false
C
Statement I is correct but Statement II is false
D
Both Statement I and II are correct
JEE Main Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
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Calculus
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