SECTION - A [CHEMISTY - MCQ] - JEE STD 11 Science Questions

MCQ 14 Marks

The alkane from below having two secondary hydrogens is :

A
4-Ethyl-3,4-dimethyloctane
B
2,2,4,4-Tetramethylhexane
✓
2,2,3,3-Tetramethylpentane
D
2,2,4,5-Tetramethylheptane

Answer

Correct option: C.

2,2,3,3-Tetramethylpentane

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MCQ 24 Marks

Given below are two statements :
Statement (I) : Corrosion is an electrochemical phenomenon in which pure metal acts as an anode and impure metal as a cathode.
Statement (II) : The rate of corrosion is more in alkaline medium than in acidic medium.
In the light of the above statements, choose the correct answer from the options given below :

A
Both Statement I and Statement II are false
B
Statement I is false but Statement II is true
C
Both Statement I and Statement II are true
✓
Statement I is true but Statement II is false

Answer

Correct option: D.

Statement I is true but Statement II is false

(D) Statement I is true but Statement II is false
Sol. Statement I :
Corrosion is an example of electrochemical phenomenon
In which pure metal act as anode and impure metal (rusted metal) act as cathode.
Statement II :
Corrosion is more favourable in acid medium than alkaline so rate of corrosion is high is acid medium then alkaline.

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MCQ 34 Marks

Residue (A) + HCl (dil.) $\rightarrow$ Compound (B)
Structure of residue (A) and compound (B)
Formed respectively is :

A
[A] [B]
(1)
B
[A] [B]
(2)
C
[A] [B]
(3)
✓
[A] [B]
(4)

Answer

Correct option: D.

	[A]	[B]
(4)

(D)

	[A]	[B]
(4)

Sol.

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MCQ 44 Marks

Identify the homoleptic complex(es) that is/are low spin.
(A) $\left[ Fe ( CN )_5 NO \right]^{2-}$
(B) $\left[ CoF _6\right]^{3-}$
(C) $\left[ Fe ( CN )_6\right]^{+}$
(D) $\left[ Co \left( NH _3\right)_6\right]^{3+}$
(E) $\left[ Cr \left( H _2 O \right)_6\right]^{2+}$
Choose the correct answer from the options given below :

A
(B) and (E) only
B
(A) and (C) only
✓
(C) and (D) only
D
(C) only

Answer

Correct option: C.

(C) (C) and (D) only
Sol. (A) $\left[ Fe ( CN )_5 NO \right]^{-2} \rightarrow$ Heteroleptic, $Fe ^{+2}, 3 d^6$, $t _{2 g}{ }^6 e _{ g }{ }^0, d^2 sp ^3$, Low spin (3d series + SFL)
(B) $\left[ CoF _6\right]^{-3} \rightarrow$ Homoleptic, $sp ^3 d^2$, High spin, $Co ^{+3}, 3 d^6(3 d$ series + WFL $)$
(C) $\left[ Fe ( CN )_6\right]^{-4} \rightarrow$ Homoleptic
$Fe ^{+2}, 3 d^6, d^2 sp ^3, t _{2 g}{ }^6 eg ^0$ Low spin
(3d series + SFL)
(D) $\left[ Co \left( NH _3\right)_6\right]^{+3} \rightarrow$ Homoleptic, $Co ^{+3} 3 d^6, d^2 sp ^3$, $t _{2 g}{ }^6 eg ^{\circ}$, Low spin (3d series + SFL)
(E) $\left[ Cr \left( H _2 O \right)_6\right]^{+2} \rightarrow$ Homoleptic
$Cr ^{+2} 3 d^4, d^2 sp ^3$, High spin $t _{2 g}{ }^3 e _{ g }{ }^1$
(3d series + WFL)

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MCQ 54 Marks

Given below are two statement :
Statement (I) : Nitrogen, sulphur, halogen and phosphorus present in an organic compound are detected by Lassaigne's Test.
Statement (II) : The elements present in the compound are converted from covalent form into ionic form by fusing the compound with Magnesium in Lassaigne's test.
In the light of the above statements, choose the correct answer from the options given below :

A
Both Statement I and Statement II are true
B
Both Statement I and Statement II are false
✓
Statement I is true but Statement II is false
D
Statement I is false but Statement II is true

Answer

Correct option: C.

Statement I is true but Statement II is false

(C) Statement I is true but Statement II is false
Sol. The elements present in the compound are converted from covalent form into ionic form by fusing the compound with sodium in Lassigne's test

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MCQ 64 Marks

Given below are two statements :
Statement (I) : A spectral line will be observed for a $2 p_x \rightarrow 2 p_y$ transition.
Statement (II) : $2 p _{ x }$ and $2 p _{ y }$ are degenerate orbitals.
In the light of the above statements, choose the correct answer from the options given below :

A
Both Statement-I and Statement-II are true.
B
Both Statement-I and Statement-II are false.
C
Statement-I is true but Statement-II is false
✓
Statement-I is false but Statement-II is true.

Answer

Correct option: D.

Statement-I is false but Statement-II is true.

(D)Statement-I is false but Statement-II is true.
Sol. No spectral line will be observed for a $2 p_x \rightarrow 2 p_y$ transition because $2 p_x$ and $2 p_y$ orbitals are degenerate orbitals.

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MCQ 74 Marks

Given below are two statements :
Statement (I) : An element in the extreme left of the periodic table forms acidic oxides.
Statement (II) : Acid is formed during the reaction between water and oxide of a reactive element present in the extreme right of the periodic table.
In the light of the above statements, choose the correct answer from the options given below :

✓
Statement-I is false but Statement-II is true.
B
Both Statement-I and Statement-II are false.
C
Statement-I is true but Statement-II is false.
D
Both Statement-I and Statement-II are true.

Answer

Correct option: A.

Statement-I is false but Statement-II is true.

(A) Statement-I is false but Statement-II is true.
Sol. Statement-I : False but Statement-II is true.
On moving left to right in periodic table nonmetallic character increases and we know that nonmetal oxides are acide in nature.
Non metallic character $\uparrow$ Acidic strength of oxide $\uparrow$

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MCQ 84 Marks

The most stable carbocation from the following is :

Answer

Correct option: A.

(A)

Sol.

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MCQ 94 Marks

The molar solubility(s) of zirconium phosphate with molecular formula $\left( Zr ^{4+}\right)_3\left( PO _4^{3-}\right)_4$ is given by relation :

A
$\left(\frac{ K _{sp }}{6912}\right)^{\frac{1}{7}}$
B
$\left(\frac{ K _{ sp }}{5348}\right)^{\frac{1}{6}}$
C
$\left(\frac{ K _{ sp }}{8435}\right)^{\frac{1}{7}}$
D
$\left(\frac{ K _{ sp}}{9612}\right)^{\frac{1}{3}}$

Answer

(A)$\left(\frac{ K _{ sp }}{6912}\right)^{\frac{1}{7}}$

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MCQ 104 Marks

Density of 3 M NaCl solution is $1.25 g / mL$. The molality of the solution is :

A
1.79 m
B
2 m
C
3 m
✓
2.79 m

Answer

Correct option: D.

2.79 m

(D) 2.79 m
Sol. $3 M NaCl , d _{ sol }=1.25 gm / mol$
$\begin{aligned} \text { Molality } & =\frac{ M \times 1000}{1000 d- M \times M _{ w }} \\ & =\frac{3000}{1250-175.5}=2.79\end{aligned}$

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MCQ 114 Marks

The correct order of the following complexes in terms of their crystal field stabilization energies is :

A
$\left[ Co \left( NH _3\right)_4\right]^{2+}<\left[ Co \left( NH _3\right)_6\right]^{2+} \leq\left[ Co ( en )_3\right]^{3+} \leq\left[ Co \left( NH _3\right)_6\right]^{3+}$
B
$\left[ Co \left( NH _3\right)_4\right]^{2+}<\left[ Co \left( NH _3\right)_6\right]^{2+}<\left[ Co \left( NH _3\right)_6\right]^{3+}<\left[ Co ( en )_3\right]^{3+}$
C
$\left[ Co \left( NH _3\right)_6\right]^{2+}<\left[ Co \left( NH _3\right)_6\right]^{3+}<\left[ Co \left( NH _3\right)_4\right]^{2+}<\left[ Co ( en )_3\right]^{3+}$
D
$\left[ Co ( en )_3\right]^{3+}<\left[ Co \left( NH _3\right)_6\right]^{3+}<\left[ Co \left( NH _3\right)_6\right]^{2+}<\left[ Co \left( NH _3\right)_4\right]^{2+}$

Answer

(B) $\left[ Co \left( NH _3\right)_4\right]^{2+}<\left[ Co \left( NH _3\right)_6\right]^{2+}<\left[ Co \left( NH _3\right)_6\right]^{3+}<\left[ Co ( en )_3\right]^{3+}$
Sol. Order of CFSE

SFL: $NH _3< en$

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MCQ 124 Marks

Match List-I with List-II.

	List-I (Partial Derivatives)		List-II (Thermodynamic Quantity)
(A)	$\left(\frac{\partial G }{\partial T }\right)_{ P }$	(I)	$C_P$
(B)	$\left(\frac{\partial H }{\partial T }\right)_{ P }$	(II)	-S
(C)	$\left(\frac{\partial G }{\partial P }\right)_{ T }$	(III)	$C_V$
(D)	$\left(\frac{\partial U }{\partial T }\right)_{ V }$	(IV)	V

Choose the correct answer from the options given below :

A
(A)-(II), (B)-(I), (C)-(III), (D)-(IV)
✓
(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
C
(A)-(I), (B)-(II), (C)-(IV), (D)-(III)
D
(A)-(II), (B)-(III), (C)-(I), (D)-(IV)

Answer

Correct option: B.

(A)-(II), (B)-(I), (C)-(IV), (D)-(III)

(B) (A)-(II), (B)-(I), (C)-(IV), (D)-(III)
Sol. (A) $dG = VdP - SdT$
Constant pressure
$
\begin{array}{l}
dG=-SdT \\
\left(\frac{\partial G}{\partial T}\right)_{p}=-S\end{array}$

(B) $dH =( dq )_{ p }= nCpdT$
$
\left(\frac{\partial H}{\partial T}\right)_{P}=C_{p}
$

(C) $dG = VdP - SdT$
At constant temperature
$
\begin{array}{l}
dG=VdP \\
\left(\frac{\partial G}{\partial P}\right)_{T}=V
\end{array}
$
(D)$
\begin{array}{l}\\dU=nC_{V} dT=(q)_{V} \\
\left(\frac{\partial U}{\partial T}\right)_{V}=C_{V}
\end{array}
$

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MCQ 134 Marks

The maximum number of RBr producing 2-methylbutane by above sequence of reactions is _________. (Consider the structural isomers only)

✓
4
B
5
C
3
D
1

Answer

Correct option: A.

(A) 4
Sol.

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MCQ 144 Marks

Match the Compounds (List-I) with the appropriate Catalyst/Reagents (List-II) for their reduction into corresponding amines.

	List-I (Compounds)	List-II (Catalyst/Reagents)
(A)		NaOH (aqueous)
(B)		$\quad H _2 / Ni$
(C)	$R - C \equiv N$	$LiAlH _4, H _2 O$
(D)		$Sn , HCl$

Choose the correct answer from the options given below:

A
(A)-(III), (B)-(II), (C)-(IV), (D)-(I)
B
(A)-(II), (B)-(IV), (C)-(III), (D)-(I)
C
(A)-(II), (B)-(I), (C)-(III), (D)-(IV)
✓
(A)-(III), (B)-(IV), (C)-(II), (D)-(I)

Answer

Correct option: D.

(A)-(III), (B)-(IV), (C)-(II), (D)-(I)

(D) (A)-(III), (B)-(IV), (C)-(II), (D)-(I)
Sol.

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MCQ 154 Marks

The species which does not undergo disproportionation reaction is :

A
$ClO _2^{-}$
✓
$ClO _4^{-}$
C
$ClO ^{-}$
D
$ClO _3^{-}$

Answer

Correct option: B.

$ClO _4^{-}$

(B) $ClO _4^{-}$
Sol. $ClO _4^{-} \rightarrow x+\{(-2) \times 4\}=-1 \Rightarrow x=+7$
Chlorine is in its maximum oxidation state, so disproportionation not possible in $ClO _4^{-}$.

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MCQ 164 Marks

When sec-butylcyclohexane reacts with bromine in the presence of sunlight, the major product is :

Answer

Correct option: D.

(D)

Sol.

Formation of more stable free radical intermediate

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MCQ 174 Marks

Consider the given figure and choose the correct option :

A
Activation energy of backward reaction is $E_1$ and product is more stable than reactant.
B
Activation energy of forward reaction is $E _1+ E _2$ and product is more stable than reactant.
✓
Activation energy of forward reaction is $E _1+ E _2$ and product is less stable than reactant.
D
Activation energy of both forward and backward reaction is $E_1+E_2$ and reactant is more stable than product.

Answer

Correct option: C.

Activation energy of forward reaction is $E _1+ E _2$ and product is less stable than reactant.

(C) Activation energy of forward reaction is $E _1+ E _2$ and product is less stable than reactant.
Sol. Activation energy of forward reaction $=E_1+E_2$
Energy of product > Energy of reactant
Stability
Reactant $>$ Product

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MCQ 184 Marks

The maximum covalency of a non-metallic group 15 element 'E' with weakest $E - E$ bond is :