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JEE SECTION - A [CHEMISTY - MCQ]

JEE Main 4-April-2025 Paper - Shift 2 · Gujarat Board (GSEB) STD 11 Science (GSEB - English Medium). 20 questions.

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SECTION - A [CHEMISTY - MCQ]

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20 questions · 18 auto-graded MCQ + 2 self-marked written.

MCQ 14 Marks
Half life of zero order reaction $A \rightarrow$ product is 1 hour, when initial concentration of reaction is $2.0$ $mol$ $L ^{-1}$. The time required to decrease concentration of A from $0.50$ to $0.25$ $mol$ $L ^{-1}$ is:
  • A
    0.5 hour
  • B
    4 hour
  • ✓
    15 min
  • D
    60 min
Answer
Correct option: C.
15 min
(C) 15 min
For zero order reaction
$\text {Half life}=\frac{A_0}{2 k} $
$60 \min =\frac{2}{2 k} $
$k=\frac{1}{60} M / min$
Now
$A _{ t }= A _{ o }- kt $
$t =\frac{ A _{ o }- A _{ t }}{ k }$
$=\frac{0.5-0.25}{1 / 60} $
$0.25 \times 60 $
$t =15$ $min$
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MCQ 24 Marks
Given below are two statements:
Statement (I) : for Image all three possible structures may be drawn as follows.

Image
Statement (II) : Structure III is most stable, as the orbitals having the lone pairs are axial, where the $\ell p - bp$ repulsion is minimum.
In the light of the above statements, choose the most appropriate answer from the options given below:
  • A
    Statement I is incorrect but Statement II is correct.
  • ✓
    Statement I is correct but Statement II is incorrect.
  • C
    Both Statement I and Statement II are correct.
  • D
    Both Statement I and Statement II are incorrect.
Answer
Correct option: B.
Statement I is correct but Statement II is incorrect.
(B) Statement I is correct but Statement II is incorrect.
Statement 1 is correct.
Statement 2 is incorrect since in $sp ^3 d$ hybridization; lone pair cannot occupy axial position.
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MCQ 44 Marks
The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively:
  • A
    B & Ga
  • B
    B & TI
  • C
    TI & B
  • ✓
    B & In
Answer
Correct option: D.
B & In
(D) B & In
IE order
$B > T \ell > Ga > Al > In$
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MCQ 54 Marks
'$X$' is the number of electrons in $t_{2 g}$ orbitals of the most stable complex ion among $\left[ Fe \left( NH _3\right)_6\right]^{3+}$, $\left[ Fe \left( Cl _6\right)\right]^{3-}$, $\left[ Fe \left( C _2 O _4\right)_3\right]^{3-}$ and $\left[ Fe \left( H _2 O \right)_6\right]^{3+}$. The nature of oxide of vanadium of the type $V _2 O _{ X }$ is:
  • A
    Acidic
  • B
    Neutral
  • C
    Basic
  • ✓
    Amphoteric
Answer
Correct option: D.
Amphoteric
(D) Amphoteric
Most stable is $\left[ Fe \left( C _2 O _4\right)_3\right]^{3-}$ due to Chelation effect.
Image
$V _2 O _5$ is amphoteric.
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MCQ 64 Marks
Consider the following plots of log of rate constant $k (\log k )$ vs $\frac{1}{T}$ for three different reactions. The correct order of activation energies of these reactions is
Image
  • ✓
    $Ea _2> Ea _1> Ea _3$
  • B
    $Ea _1> Ea _3> Ea _2$
  • C
    $Ea _1> Ea _2> Ea _3$
  • D
    $Ea _3> Ea _2> Ea _1$
Answer
Correct option: A.
$Ea _2> Ea _1> Ea _3$
(A) $Ea _2 > Ea _1 > Ea _3$
$\begin{array}{l} K = A e^{- Ea / RT } \\ \log k =\log A -\frac{ Ea }{2.303 RT }\end{array}$
For graph between logk with $\frac{1}{T}$
$\mid$ Slope of curve $\mid$ $=\frac{ Ea }{2.303 R }$
From given graph
Magnitude of slope $\Rightarrow(2) > (1) > (3)$
Hence $Ea _2 > Ea _1 > Ea _3$
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MCQ 74 Marks
Given below are two statements :
Statement (I) : The first ionisation enthalpy of group 14 elements is higher than the corresponding elements of group 13.
Statement (II) : Melting points and boiling points of group 13 elements are in general much higher than those the corresponding elements of group 14 . In the light of the above statements, choose the most appropriate answer from the options given below :
  • ✓
    Statement I is correct but Statement II is incorrect
  • B
    Statement I is incorrect but Statement II is correct
  • C
    Both Statement I and Statement II are incorrect
  • D
    Both Statement I and Statement II are correct
Answer
Correct option: A.
Statement I is correct but Statement II is incorrect
(A) Statement I is correct but Statement II is incorrect
Statement 1 is correct since left to right 1 E increases in general in periodic table.
Statement 2 is incorrect since M.P. of group 14 elements is more than group 13 elements.
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MCQ 84 Marks
Consider the ground state of chromium atom $( Z =24)$. How many electrons are with Azimuthal quantum number $l=1$ and $l=2$ respectively ?
  • A
    12 and 4
  • B
    16 and 4
  • ✓
    12 and 5
  • D
    16 and 5
Answer
Correct option: C.
12 and 5
(C) 12 and 5
Image
electrons having $\ell=1 \Rightarrow 12$
electrons having $\ell=2 \Rightarrow 5$
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MCQ 94 Marks
Consider the given data :
(a) $HCl ( g )+10 H _2 O ( l ) \rightarrow HCl .10 H _2 O$$\quad$$\Delta H =-69.01$ $kJ$ $mol ^{-1}$
(b) $HCl ( g )+40 H _2 O ( l ) \rightarrow HCl .40 H _2 O$$\quad$$\Delta H =-72.79$ $kJ$ $mol ^{-1}$
Choose the correct statement :
  • A
    Dissolution of gas in water is an endothermic process
  • ✓
    The heat of solution depends on the amount of solvent.
  • C
    The heat of dilution for the $HCl \left( HCl.10 H _2 O\right.$ to $HCl.40 H _2 O$ ) is $3.78 kJ mol ^{-1}$.
  • D
    The heat of formation of HCl solution is represented by both (a) and (b)
Answer
Correct option: B.
The heat of solution depends on the amount of solvent.
(B) The heat of solution depends on the amount of solvent.
From the given information
$\Delta H$ is negative so it means dissolution of gas $HCl ( g )$ is exothermic.
$HCl(g)+10 H_2 O(l) \rightarrow HCl .10 H_2 O \qquad\ldots (1)$
$\Delta H_1=-69.01 \frac{kJ}{mol} $
$HCl(g)+40 H_2 O(l) \rightarrow HCl .40 H_2 O \qquad\ldots (2)$
$\Delta H_2=-72.79 \frac{kJ}{mol}$
Hence heat of solution depends upon amount of solvent
By equation.....(2) - equation ....(1)
$HCl .10 H _2 O +30 H _2 O (\ell) \rightarrow HCl .40 H _2 O$
So Heat of dilution $=-72.79-(-69.01)$
$=-3.78 \frac{kJ}{ mol }$
Hence option (C) is incorrect.
For heat of formation reactant should be in elemental form hence option (D) is incorrect
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MCQ 104 Marks
The correct order of $\left[ FeF _6\right]^{3-},\left[ CoF _6\right]^{3-},\left[ Ni ( CO )_4\right]$ and $\left[ Ni ( CN )_4\right]^{2-}$ complex species based on the number of unpaired electrons present is :
  • A
    $\left[ FeF _6\right]^{3-}>\left[ CoF _6\right]^{3-}>\left[ Ni ( CN )_4\right]^{2-}>\left[ Ni ( CO )_4\right]$
  • B
    $\left[ Ni ( CN )_4\right]^{2-}>\left[ FeF _6\right]^{3-}>\left[ CoF _6\right]^{3-}>\left[ Ni ( CO )_4\right]$
  • C
    $\left[ CoF _6\right]^{3-}>\left[ FeF _6\right]^{3-}>\left[ Ni ( CO )_4\right]>\left[ Ni ( CN )_4\right]^{2-}$
  • ✓
    $\left[ FeF _6\right]^{3-}>\left[ CoF _6\right]^{3-}>\left[ Ni ( CN )_4\right]^{2-}=\left[ Ni ( CO )_4\right]$
Answer
Correct option: D.
$\left[ FeF _6\right]^{3-}>\left[ CoF _6\right]^{3-}>\left[ Ni ( CN )_4\right]^{2-}=\left[ Ni ( CO )_4\right]$
(D) $\left[ FeF _6\right]^{3-}>\left[ CoF _6\right]^{3-}>\left[ Ni ( CN )_4\right]^{2-}=\left[ Ni ( CO )_4\right]$
Image
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MCQ 114 Marks
A toxic compound "A" when reacted with NaCN in aqueous acidic medium yields an edible cooking component and food preservative 'B'. "B" is converted to "C" by diborane and can be used as an additive to petrol to reduce emission. "C" upon reaction with oleum at $140^{\circ} C$ yields an inhalable anesthetic "D". Identify "A", "B", "C" and "D", respectively.
  • A
    Methanol; formaldehyde; methyl chloride; chloroform
  • B
    Ethanol; acetonitrile; ethylamine; ethylene
  • ✓
    Methanol; acetic acid; ethanol; diethyl ether
  • D
    Acetaldehyde; 2- hydroxypropanoic acid; propanoic acid; dipropyl ether
Answer
Correct option: C.
Methanol; acetic acid; ethanol; diethyl ether
(C) Methanol; acetic acid; ethanol; diethyl ether
Image
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MCQ 124 Marks
Match List-I with List-II -
List-I (Separation of)List-II (SeparationTechnique)
(A) Aniline from aniline-water mixture(I) Simple distillation
(B) Glycerol from spent-lye in soap industry(II) Fractional distillation
(C) Different fractions of crude oil in petroleum industry(III) Distillation at reduced pressure
(D) ChloroformAniline mixture(IV) Steam distillation
Choose the correct answer from the options given below :
  • ✓
    (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
  • B
    (A)-(I), (B)-(II), (C)-(III), (D)-(IV)
  • C
    (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
  • D
    (A)-(II), (B)-(I), (C)-(IV), (D)-(III)
Answer
Correct option: A.
(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
(A) (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
(A) Aniline $- H _2 O$ : Steam Distillation
(B) Glycerol from spent-lye in soap industry - Distillation under reduced pressure
(C) Different fraction of crude oil in petroleum industry - Fractional distillation
(D) $CHCl _3$ - Aniline - Simple distillation
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MCQ 134 Marks
The IUPAC name of the following compound is -
Image
  • A
    4-Hydroxyhept-1-en-6-yne
  • B
    4-Hydroxyhept-6-en-1-yne
  • C
    Hept-6-en-1-yn-4-ol
  • ✓
    Hept-1-en-6-yn-4-ol
Answer
Correct option: D.
Hept-1-en-6-yn-4-ol
(D) Hept-1-en-6-yn-4-ol
Image
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MCQ 144 Marks
Given below are two statements :
Statement (I) : Molal depression constant $K _{ f }$ is given by $\frac{ M _1 R T_f}{\Delta S_{\text {fus }}}$, where symbols have their usual meaning.
Statement (II) : $K _{ f }$ for benzene is less than the $K _{ f }$ for water.
In the light of the above statements, choose the most appropriate answer from the options given below :
  • A
    Statement I is incorrect but Statement II is correct
  • B
    Both Statement I and Statement II are incorrect
  • C
    Both Statement I and Statement II are correct
  • ✓
    Statement I is correct but Statement II is incorrect
Answer
Correct option: D.
Statement I is correct but Statement II is incorrect
(D) Statement I is correct but Statement II is incorrect
Statement-I
Molar depression constant $k _f=\frac{ M _1 RT _{ f }^2}{\Delta H _{\text {fus }}}$
$k _f=\frac{ M _1 RT _{ f }}{\left[\frac{\Delta H _{\text {fus }}}{ T _{ f }}\right]} $
$k _f=\frac{ M _1 RT _f}{\Delta S_{\text {fus }}}$
Hence statement-I is correct
but $k _{ f }$ for benzene $=5.12 \frac{{ }^{\circ} C }{\text { molal }}$
$k _{ f }$ for water $=1.86 \frac{{ }^{\circ} C }{\text { molal }}$ Hence statement- II is incorrect
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MCQ 154 Marks
Given below are two statements :
Statement (I) : Alcohols are formed when alkyl chlorides are treated with aqueous potassium hydroxide by elimination reaction.
Statement (II) : In alcoholic potassium hydroxide, alkyl chlorides form alkenes by abstracting the hydrogen from the $\beta$-carbon.
In the light of the above statements, choose the most appropriate answer from the options given below :
  • A
    Both Statement I and Statement II are incorrect
  • B
    Statement I is incorrect but Statement II is correct
  • C
    Statement I is correct but Statement II is incorrect
  • D
    Both Statement I and Statement II are correct
Answer
(B) Statement I is incorrect but Statement II is correct
Statement (I) :
$R - Cl \xrightarrow{( aq , KOH )} R - OH \left( S _{ N }\right.$ reaction$)$
Statement (II) :
Image
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MCQ 164 Marks
In which pairs, the first ion is more stable than the second?
Image
  • A
    (B) & (D) only
  • ✓
    (A) & (B) only
  • C
    (B) & (C) only
  • D
    (A) & (C) only
Answer
Correct option: B.
(A) & (B) only
(B) (A) & (B) only
Image
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MCQ 184 Marks
Which among the following compounds give yellow solid when reacted with $NaOI / NaOH$ ?
Image
Choose the correct answer from the options given below :
  • A
    (B), (C) and (E) Only
  • ✓
    (A) and (C) Only
  • C
    (C) and (D) Only
  • D
    (A), (C) and (D) Only
Answer
Correct option: B.
(A) and (C) Only
(B) (A) and (C) Only
Image
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MCQ 194 Marks
The incorrect relationship in the following pairs in relation to ionisation enthalpies is :
  • A
    $Mn ^{+}< Cr ^{+}$
  • B
    $Mn ^{+}< Mn ^{2+}$
  • C
    $Fe ^{2+}< Fe ^{3+}$
  • ✓
    $Mn ^{2+}< Fe ^{2+}$
Answer
Correct option: D.
$Mn ^{2+}< Fe ^{2+}$
(D) $Mn ^{2+}< Fe ^{2+}$
$Mn ^{2+}:[ Ar ] 3 d^5$
Half filled stability
More 1 E than $Fe ^{2+}$
$Fe ^{2+}:[ Ar ] 3 d^6$
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MCQ 204 Marks
The correct order of basicity for the following molecules is :
Image
  • A
    P $>$ Q $>$ R
  • B
    R $>$ P $>$ Q
  • C
    Q $>$ P $>$ R
  • ✓
    R $>$ Q $>$ P
Answer
Correct option: D.
R $>$ Q $>$ P
(D) R $>$ Q $>$ P
Image
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