JEE MAIN - Chemistry (2023 - 31st January Evening Shift)

1
When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of $A$ ?
Answer
(A)
$\mathrm{C}_{9} \mathrm{H}_{8}$
2
Cyclohexylamine when treated with nitrous acid yields $(\mathrm{P})$. On treating $(\mathrm{P})$ with $\mathrm{PCC}$ results in (Q). When $(\mathrm{Q})$ is heated with dil. $\mathrm{NaOH}$ we get $(\mathrm{R})$ The final product (R) is :
Answer
(B)
JEE Main 2023 (Online) 31st January Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 73 English Option 2
3
Compound $\mathrm{A}, \mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{5}$, given a tetraacetate with $\mathrm{Ac}_{2} \mathrm{O}$ and oxidation of $\mathrm{A}$ with $\mathrm{Br}_{2}-\mathrm{H}_{2} \mathrm{O}$ gives an acid, $\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{6}$. Reduction of $\mathrm{A}$ with $\mathrm{HI}$ gives isopentane. The possible structure of $\mathrm{A}$ is
Answer
(B)
JEE Main 2023 (Online) 31st January Evening Shift Chemistry - Alcohols, Phenols and Ethers Question 58 English Option 2
4
An organic compound $[\mathrm{A}]\left(\mathrm{C}_{4} \mathrm{H}_{11} \mathrm{~N}\right)$, shows optical activity and gives $\mathrm{N}_{2}$ gas on treatment with $\mathrm{HNO}_{2}$. The compound $[\mathrm{A}]$ reacts with $\mathrm{PhSO}_{2} \mathrm{Cl}$ producing a compound which is soluble in $\mathrm{KOH}$. The structure of $\mathrm{A}$ is :
Answer
(B)
JEE Main 2023 (Online) 31st January Evening Shift Chemistry - Compounds Containing Nitrogen Question 73 English Option 2
5
Which of the following elements have half-filled f-orbitals in their ground state?

(Given : atomic number $\mathrm{Sm}=62 ; \mathrm{Eu}=63 ; \mathrm{Tb}=65 ; \mathrm{Gd}=64, \mathrm{Pm}=61$ )

A. $\mathrm{Sm}$

B. Eu

C. $\mathrm{Tb}$

D. Gd

E. $\mathrm{Pm}$

Choose the correct answer from the options given below :
Answer
(A)
B and D only
6
Evaluate the following statements for their correctness.

A. The elevation in boiling point temperature of water will be same for $0.1 \mathrm{M} \, \mathrm{NaCl}$ and $0.1 \mathrm{M}$ urea.

B. Azeotropic mixtures boil without change in their composition.

C. Osmosis always takes place from hypertonic to hypotonic solution.

D. The density of $32 \% \, \mathrm{H}_{2} \mathrm{SO}_{4}$ solution having molarity $4.09 ~\mathrm{M}$ is approximately $1.26 \mathrm{~g} \mathrm{~mL}^{-1}$

E. A negatively charged sol is obtained when KI solution is added to silver nitrate solution.

Choose the correct answer from the options given below :
Answer
(C)
B and D only
7
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 :
Answer
(D)
$\mathrm{D}>\mathrm{B}>\mathrm{C}>\mathrm{A}$
8
In Dumas method for the estimation of $\mathrm{N}_{2}$, the sample is heated with copper oxide and the gas evolved is passed over :
Answer
(B)
Copper gauze
9
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 :
Answer
(D)
(A) is false but (R) is true
10
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:
Answer
(B)
cyclohexa-1, 4-diene
11
Given below are two statements :

Statement I: Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green

Statement II: The green colour observed is due to the formation of copper(I) metaborate

In light of the above statements, choose the most appropriate answer from the options given below :
Answer
(A)
Both Statement I and Statement II are false
12
In the following halogenated organic compounds, the one with the maximum number of chlorine atoms in its structure is :
Answer
(A)
Gammaxene
13
The incorrect statement for the use of indicators in acid-base titration is :
Answer
(B)
Methyl orange may be used for a weak acid vs weak base titration.
14
Assume carbon burns according to the following equation :

$2 \mathrm{C}_{(\mathrm{s})}+\mathrm{O}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{CO}(\mathrm{g})$

when $12 \mathrm{~g}$ carbon is burnt in $48 \mathrm{~g}$ of oxygen, the volume of carbon monoxide produced is ___________ $\times 10^{-1} \mathrm{~L}$ at STP [nearest integer]

[Given: Assume $\mathrm{CO}$ as ideal gas, Mass of $\mathrm{C}$ is $12 \mathrm{~g} \mathrm{~mol}^{-1}$, Mass of $\mathrm{O}$ is $16 \mathrm{~g} \mathrm{~mol}^{-1}$ and molar volume of an ideal gas at STP is $22.7 \mathrm{~L} \mathrm{~mol}^{-1}$ ]
Answer
227
15
The number of molecules which gives the haloform test among the following molecules is ________.

JEE Main 2023 (Online) 31st January Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 72 English
Answer
3
16
Amongst the following, the number of species having the linear shape is _________.

$\mathrm{XeF}_{2}, \mathrm{I}_{3}^{+}, \mathrm{C}_{3} \mathrm{O}_{2}, \mathrm{I}_{3}^{-}, \mathrm{CO}_{2}, \mathrm{SO}_{2}, \mathrm{BeCl}_{2}$ and $\mathrm{BCl}_{2}^{\ominus}$
Answer
5
17
Enthalpies of formation of $\mathrm{CCl}_{4}(\mathrm{~g}), \mathrm{H}_{2} \mathrm{O}(\mathrm{g}), \mathrm{CO}_{2}(\mathrm{~g})$ and $\mathrm{HCl}(\mathrm{g})$ are $-105,-242,-394$ and $-92 ~\mathrm{kJ}$ $\mathrm{mol}^{-1}$ respectively. The magnitude of enthalpy of the reaction given below is _________ $\mathrm{kJ} ~\mathrm{mol}^{-1}$. (nearest integer)

$\mathrm{CCl}_{4}(\mathrm{~g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})+4 \mathrm{HCl}(\mathrm{g})$
Answer
173
18
At $298 \mathrm{~K}$, the solubility of silver chloride in water is $1.434 \times 10^{-3} \mathrm{~g} \mathrm{~L}^{-1}$. The value of $-\log \mathrm{K}_{\mathrm{sp}}$ for silver chloride is _________.

(Given mass of $\mathrm{Ag}$ is $107.9 \mathrm{~g} \mathrm{~mol}^{-1}$ and mass of $\mathrm{Cl}$ is $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$ )
Answer
10
19
The resistivity of a $0.8 \mathrm{M}$ solution of an electrolyte is $5 \times 10^{-3} \Omega~ \mathrm{cm}$.

Its molar conductivity is _________ $\times 10^{4}~ \Omega^{-1} \mathrm{~cm}^{2} \mathrm{~mol}^{-1}$. (Nearest integer)
Answer
25
20
A sample of a metal oxide has formula $\mathrm{M}_{0.83} \mathrm{O}_{1.00}$. The metal $\mathrm{M}$ can exist in two oxidation states $+2$ and $+3$.

In the sample of $\mathrm{M}_{0.83} \mathrm{O}_{1.00}$, the percentage of metal ions existing in $+2$ oxidation state is __________ $\%$. (nearest integer)
Answer
59
21
If the CFSE of $\left[\mathrm{Ti}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}$ is $-96.0 \mathrm{~kJ} / \mathrm{mol}$, this complex will absorb maximum at wavelength ___________ $\mathrm{nm}$. (nearest integer)

Assume Planck's constant (h) $=6.4 \times 10^{-34} \mathrm{Js}$, Speed of light $(\mathrm{c})=3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}$ and Avogadro's

Constant $\left(\mathrm{N}_{\mathrm{A}}\right)=6 \times 10^{23} / \mathrm{mol}$
Answer
480
22
The rate constant for a first order reaction is $20 \mathrm{~min}^{-1}$. The time required for the initial concentration of the reactant to reduce to its $\frac{1}{32}$ level is _______ $\times 10^{-2} \mathrm{~min}$. (Nearest integer)

(Given : $\ln 10=2.303$ and $$ \log 2=0.3010 \text { )}$$
Answer
17