JEE MAIN - Chemistry (2025 - 22nd January Morning Shift)
1
Which of the following electrolyte can be used to obtain $\mathrm{H}_2 \mathrm{~S}_2 \mathrm{O}_8$ by the process of electrolysis ?
Answer
(A)
Concentrated solution of sulphuric acid
2
Which of the following statement is not true for radioactive decay?
Answer
(B)
Decay constant increases with increase in temperature.
3
Given below are two statements :
Statement I : $\quad \mathrm{CH}_3-\mathrm{O}-\mathrm{CH}_2-\mathrm{Cl}$ will undergo $\mathrm{S}_{\mathrm{N}} 1$ reaction though it is a primary halide.
Statement II : will not undergo $\mathrm{S}_{\mathrm{N}} 2$ reaction very easily though it is a primary halide.
In the light of the above statements, choose the most appropriate answer from the options given below :
Answer
(B)
Both Statement I and Statement II are correct
4
The products formed in the following reaction sequence are :
Answer
(D)
5
From the magnetic behaviour of $\left[\mathrm{NiCl}_4\right]^{2-}$ (paramagnetic) and $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ (diamagnetic), choose the correct geometry and oxidation state.
Choose the correct answer from the options given below :
Answer
(A)
(A)-(IV), (B)-(I), (C)- (II), (D)-(III)
8
A vessel at 1000 K contains $\mathrm{CO}_2$ with a pressure of 0.5 atm . Some of $\mathrm{CO}_2$ is converted into CO on addition of graphite. If total pressure at equilibrium is 0.8 atm , then Kp is :
Answer
(D)
1.8 atm
9
A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A . The amount of the aluminium deposited at the cathode is __________ .
[Given : molar mass of aluminium and chlorine are $27 \mathrm{~g} \mathrm{~mol}^{-1}$ and $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively. Faraday constant $\left.=96500 \mathrm{C} \mathrm{~mol}^{-1}\right]$
Answer
(C)
0.336 g
10
How many different stereoisomers are possible for the given molecule?
Answer
(D)
4
11
A liquid when kept inside a thermally insulated closed vessel at $25^{\circ} \mathrm{C}$ was mechanically stirred from outside. What will be the correct option for the following thermodynamic parameters ?
Answer
(B)
$\Delta \mathrm{U}>0, \mathrm{q}=0, \mathrm{w}>0$
12
Lanthanoid ions with $4 \mathrm{f}^7$ configuration are :
(A) $\mathrm{Eu}^{2+}$
(B) $\mathrm{Gd}^{3+}$
(C) $\mathrm{Eu}^{3+}$
(D) $\mathrm{Tb}^{3+}$
(E) $ \mathrm{Sm}^{2+}$
Choose the correct answer from the options given below :
Answer
(D)
(A) and (B) only
13
The incorrect statements regarding geometrical isomerism are :
(A) Propene shows geometrical isomerism.
(B) Trans isomer has identical atoms/groups on the opposite sides of the double bond.
(C) Cis-but-2-ene has higher dipole moment than trans-but-2-ene.
(D) 2-methylbut-2-ene shows two geometrical isomers.
(E) Trans-isomer has lower melting point than cis isomer.
Choose the correct answer from the options given below :
Answer
(B)
(A), (D) and (E) Only
14
Given below are two statements :
Statement I : One mole of propyne reacts with excess of sodium to liberate half a mole of $\mathrm{H}_2$ gas.
Statement II : Four g of propyne reacts with $\mathrm{NaNH}_2$ to liberate $\mathrm{NH}_3$ gas which occupies 224 mL at STP.
In the light of the above statements, choose the most appropriate answer from the options given below :
Answer
(D)
Statement I is correct but Statement II is incorrect
15
Which of the following electronegativity order is incorrect?
Answer
(C)
$\mathrm{Al}<\mathrm{Mg}<\mathrm{B}<\mathrm{N}$
16
Arrange the following solutions in order of their increasing boiling points.
(i) $10^{-4} \mathrm{M} \mathrm{NaCl}$
(ii) $10^{-4} \mathrm{M}$ Urea
(iii) $10^{-3} \mathrm{M} \mathrm{NaCl}$
(iv) $10^{-2} \mathrm{M} \mathrm{NaCl}$
Answer
(B)
(ii) $<($ i $)<($ iii $)<($ iv $)$
17
In which of the following complexes the CFSE, $\Delta_o$ will be equal to zero?
Some $\mathrm{CO}_2$ gas was kept in a sealed container at a pressure of 1 atm and at 273 K . This entire amount of $\mathrm{CO}_2$ gas was later passed through an aqueous solution of $\mathrm{Ca}(\mathrm{OH})_2$. The excess unreacted $\mathrm{Ca}(\mathrm{OH})_2$ was later neutralized with 0.1 M of 40 mL HCl . If the volume of the sealed container of $\mathrm{CO}_2$ was $x$, then $x$ is ____________ $\mathrm{cm}^3$ (nearest integer).
[Given : The entire amount of $\mathrm{CO}_2(\mathrm{~g})$ reacted with exactly half the initial amount of $\mathrm{Ca}(\mathrm{OH})_2$ present in the aqueous solution.]
Answer
45
24
In Carius method for estimation of halogens, 180 mg of an organic compound produced 143.5 mg of AgCl . The percentage composition of chlorine in the compound is _________ %. (Given : molar mass in $\mathrm{g} \mathrm{~mol}^{-1}$ of $\mathrm{Ag}: 108, \mathrm{Cl}: 35.5$ )
Answer
20
25
$\mathrm{A \rightarrow B}$
The molecule A changes into its isomeric form B by following a first order kinetics at a temperature of 1000 K . If the energy barrier with respect to reactant energy for such isomeric transformation is $191.48 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and the frequency factor is $10^{20}$, the time required for $50 \%$ molecules of A to become B is __________ picoseconds (nearest integer). $\left[\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right]$