1
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Arrange the following orbitals in decreasing order of energy.

A. $\mathrm{n}=3, \mathrm{l}=0, \mathrm{~m}=0$

B. $\mathrm{n}=4, \mathrm{l}=0, \mathrm{~m}=0$

C. $\mathrm{n}=3, \mathrm{l}=1, \mathrm{~m}=0$

D. $\mathrm{n}=3, \mathrm{l}=2, \mathrm{~m}=1$

The correct option for the order is :
A
$\mathrm{B}>\mathrm{D}>\mathrm{C}>\mathrm{A}$
B
$\mathrm{A}>\mathrm{C}>\mathrm{B}>\mathrm{D}$
C
$\mathrm{D}>\mathrm{B}>\mathrm{A}>\mathrm{C}$
D
$\mathrm{D}>\mathrm{B}>\mathrm{C}>\mathrm{A}$
2
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
In Dumas method for the estimation of $\mathrm{N}_{2}$, the sample is heated with copper oxide and the gas evolved is passed over :
A
Copper oxide
B
Copper gauze
C
$\mathrm{Pd}$
D
$\mathrm{Ni}$
3
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R)

Assertion (A): The first ionization enthalpy of $3 \mathrm{~d}$ series elements is more than that of group 2 metals

Reason (R): In 3d series of elements successive filling of d-orbitals takes place.

In the light of the above statements, choose the correct answer from the options given below :
A
Both (A) and (R) are true and (R) is the correct explanation of (A)
B
(A) is true but (R) is false
C
Both (A) and (R) are true but $(\mathbf{R})$ is not the correct explanation of (A)
D
(A) is false but (R) is true
4
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A hydrocarbon ' $\mathrm{X}$ ' with formula $\mathrm{C}_{6} \mathrm{H}_{8}$ uses two moles of $\mathrm{H}_{2}$ on catalytic hydrogenation of its one mole. On ozonolysis, ' $\mathrm{X}$ ' yields two moles of methane dicarbaldehyde. The hydrocarbon ' $\mathrm{X}$ ' is:
A
hexa-1, 3, 5-triene
B
cyclohexa-1, 4-diene
C
cyclohexa - 1,3 - diene
D
1-methylcyclopenta-1, 4-diene
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