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

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SECTION - A [CHEMISTY - MCQ]

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20 questions · self-marked practice — reveal the answer and mark yourself.

MCQ 14 Marks

Given below are two statements :
1 M aqueous solution of each of $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}, \mathrm{AgNO}_{3}$, $\mathrm{Hg}_{2}\left(\mathrm{NO}_{3}\right)_{2} ; \mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}$ are electrolysed using inert electrodes,
Given : $\mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}^{\theta}=0.80 \mathrm{~V}, \mathrm{E}_{\mathrm{Hg}_{2}^{2+} / \mathrm{Hg}}^{\theta}=0.79 \mathrm{~V}$,
$\mathrm{E}_{\mathrm{Cu}^{2+} / \mathrm{Cu}}^{\theta}=0.24 \mathrm{~V}$ and $\mathrm{E}_{\mathrm{Mg}^{2+} / \mathrm{Mg}}^{\theta}=-2.37 \mathrm{~V}$
Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be $\mathrm{Ag}, \mathrm{Hg}$ and Cu
Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statement, choose the most appropriate answer from the options given below

A
Both statement I and statement II are incorrect
B
Statement I is correct but statement II is incorrect
C
Both statement I and statement II are correct
D
Statement I is incorrect but statement II is correct

Answer

B. Statement I is correct but statement II is incorrect
Statement-II $\Rightarrow$ At cathode, instead of $\mathrm{Mg}, \mathrm{H}_{2} \mathrm{O}_{(\ell)}$ will reduce & evolve $\mathrm{H}_{2}$ gas.

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MCQ 24 Marks

The correct statements from the following are :
(A) $\mathrm{Tl}^{3+}$ is a powerful oxidising agent
(B) $\mathrm{Al}^{3+}$ does not get reduced easily
(C) Both $\mathrm{Al}^{3+}$ and $\mathrm{Tl}^{3+}$ are very stable in solution
(D) $\mathrm{Tl}^{+}$is more stable than $\mathrm{Tl}^{3+}$
(E) $\mathrm{Al}^{3+}$ and $\mathrm{Tl}^{+}$are highly stable
Choose the correct answer from the options given below :

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

Answer

B. (A), (B), (D) and (E) only
(i) True, $\mathrm{T} \ell^{+}$is more stable than $\mathrm{T} \ell^{3+}$, due to inert pair effect. So $T \ell^{3+}$ is a powerful oxidising agent.
(ii) True, $\mathrm{E}_{\mathrm{Al}^{3+/ A 1}}^{0}=-1.66 \mathrm{~V}$. So it is difficult to reduce $\mathrm{A} \ell^{3+}$. So $\mathrm{A} \ell^{3+}$ is highly stable.
(iii) False, as $\mathrm{T} \ell^{3+}$ is unstable
(iv) True, $\mathrm{T} \ell^{+}$is more stable than $\mathrm{T} \ell^{3+}$
(v) True, $\mathrm{A} \ell^{3+}$ and $\mathrm{T} \ell^{+}$are highly stable

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MCQ 34 Marks

The extra stability of half-filled subshell is due to
(A) Symmetrical distribution of electrons
(B) Smaller coulombic repulsion energy
(C) The presence of electrons with the same spin in non-degenerate orbitals
(D) Larger exchange energy
(E) Relatively smaller shielding of electrons by one another
Identify the correct statements

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

Answer

B. (A), (B), (D) and (E) only
Extra stability of half filled is due to :
(i) Symmetrical distribution of electrons
(ii) Large exchange energy
(iii) Smaller coulombic repulsion
(iv) Smaller shielding of electrons by one another

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MCQ 44 Marks

Given below are two statements :

In the light of the above statements, choose the most appropriate answer from the options given below :

A
Statement I is correct but statement II is incorrect
B
Statement I is correct but statement II is incorrect
C
Both statement I and statement II are incorrect
D
Both statement I and statement II are correct

Answer

A. Statement I is correct but statement II is incorrect

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MCQ 54 Marks

The number of optically active products obtained from the complete ozonolysis of the given compound is :

A
2
B
0
C
1
D
4

Answer

B. 0

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MCQ 64 Marks

The number of unpaired electrons responsible for the paramagnetic nature of the following complex species are respectively :
$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-},\left[\mathrm{FeF}_{6}\right]^{3-},\left[\mathrm{CoF}_{6}\right]^{3-},\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-}$

A
$1,5,4,2$
B
$1,5,5,2$
C
$1,1,4,2$
D
$1,4,4,2$

Answer

A. $1,5,4,2$
$\quad\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-} \quad \mathrm{Fe}^{3+} \quad 3 \mathrm{~d}^{5} \quad \mathrm{t}_{2 \mathrm{~g}}^{2,2,1} \quad \mathrm{e}_{\mathrm{g}}^{0,0} \quad$ unpaired $\mathrm{e}^{-}=1$
$\left[\begin{array}{lllll}\mathrm{FeF}_{6}\end{array}\right]^{3-} \quad \mathrm{Fe}^{3+} \quad 3 \mathrm{~d}^{5} \quad \mathrm{t}_{2 \mathrm{~g}}^{1,1,1} \quad \mathrm{e}_{\mathrm{g}}^{1,1}$ unpaired $\mathrm{e}^{-}=5$
$\left[\mathrm{CoF}_{6}\right]^{3-} \quad \mathrm{Co}^{3+} 3 \mathrm{~d}^{6} \quad \mathrm{t}_{2 \mathrm{~g}}^{2,1,1} \quad \mathrm{e}_{\mathrm{g}}^{1}$, unpaired $\mathrm{e}^{-}=4$
$\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{3-} \mathrm{Mn}^{3+} 3 \mathrm{~d}^{4} \quad \mathrm{t}_{2 \mathrm{~g}}^{2,1,1} \quad \mathrm{e}_{\mathrm{g}}^{0,0} \quad$ unpaired $\mathrm{e}^{-}=2$

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MCQ 74 Marks

In $\mathrm{SO}_{2}, \mathrm{NO}_{2}^{-}$and $\mathrm{N}_{3}^{-}$the hybridizations at the central atom are respectively :

A
$\mathrm{sp}^{2}, \mathrm{sp}^{2}$ and sp
B
$\mathrm{sp}^{2}, \mathrm{sp}$ and sp
C
$\mathrm{sp}^{2}, \mathrm{sp}^{2}$ and $\mathrm{sp}^{2}$
D
$\mathrm{sp}, \mathrm{sp}^{2}$ and sp

Answer

A. $\mathrm{sp}^{2}, \mathrm{sp}^{2}$ and sp

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MCQ 84 Marks

Match List-I with List-II

List-I		List-II
(A)	Solution of chloroform and acetone	(I)	Minimum boiling azeotrope
(B)	Solution of ethanol and water	(II)	Dimerizes
(C)	Solution of benzene and toluene	(III)	Maximum boiling azeotrope
(D)	Solution of acetic acid in benzene	(IV)	$\Delta \mathrm{V}_{\text {mix }}=0$

Choose the correct answer from the options given below :

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

Answer

A. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
(A) Solution of chloroform and acetone shows -ve deviation, so maximum boiling azeotrope.
(B) Solution of ethanol & water shows +ve deviation. So minimum boiling azeotrope.
(C) Solution of benzene and toluene form ideal solution. $\Delta \mathrm{V}_{\text {mix }}=0$.
(D) Acetic acid in benzene form dimer.

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MCQ 94 Marks

Match List-I with List-II

List-I Complex		List-II Primary valency and Secondary valency
(A)	$\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$	(I)	3 $\quad$ 6
(B)	$\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}\left(\mathrm{NO}_{2}\right)\right]$	(II)	3 $\quad$ 4
(C)	$\mathrm{Hg}\left[\mathrm{Co}(\mathrm{SCN})_{4}\right]$	(III)	2 $\quad$ 6
(D)	$[\mathrm{Mg}(\mathrm{EDTA})]^{2-}$	(IV)	2 $\quad$ 4

Choose the correct answer from the options given below :

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

Answer

B. (A)-(I), (B)-(IV), (C)-(II), (D)-(III)
Primary valency $=$ Oxidation state Secondary valency $=$ Co-ordination number

	Complex	Primary valency	Secondary valency
(A)	$\left[\mathrm{Co}(\mathrm{en})_{2} \mathrm{Cl}_{2}\right] \mathrm{Cl}$	3	6
(B)	$\left[\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}\left(\mathrm{NO}_{2}\right)\right]$	2	4
(C)	$\mathrm{Hg}\left[\mathrm{Co}(\mathrm{SCN})_{4}\right]$	3	4
(D)	$[\mathrm{Mg}(\mathrm{EDTA})]^{2-}$	2	6

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MCQ 104 Marks

The descending order of basicity of following amines is :

Choose the correct answer from the options given below :

A
B $>$ E $>$ D $>$ A $>$ C
B
E $>$ D $>$ B $>$ A $>$ C
C
E $>$ D $>$ A $>$ B $>$ C
D
E $>$ A $>$ D $>$ C $>$ B

Answer

B. E $>$ D $>$ B $>$ A $>$ C

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MCQ 114 Marks

X ' is the number of acidic oxides among $\mathrm{VO}_{2}$,
$\mathrm{V}_{2} \mathrm{O}_{3}, \mathrm{CrO}_{3}, \mathrm{~V}_{2} \mathrm{O}_{5}$ and $\mathrm{Mn}_{2} \mathrm{O}_{7}$. The primary valency of cobalt in $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right)_{3}\right]_{2}\left(\mathrm{SO}_{4}\right)_{3}$ is Y .
The value of $\mathrm{X}+\mathrm{Y}$ is :

A
5
B
4
C
2
D
3

Answer

A. 5
$\mathrm{CrO}_{3}=$ Acidic
$\mathrm{Mn}_{2} \mathrm{O}_{7}=$ Acidic
$\therefore \mathrm{x}=2$
$\left[{ }^{\text {III }} \mathrm{Co}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right)_{3}\right]_{2}\left(\mathrm{SO}_{4}\right)_{3} \rightleftharpoons$
$2\left[\mathrm{Col}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right)_{3}\right]^{3+}+3 \mathrm{SO}_{4}^{2-}$
$\therefore$ Primary valency $=3$
$\therefore \mathrm{x}+\mathrm{y}=5$

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MCQ 124 Marks

Liquid $A$ and $B$ form an ideal solution. The vapour pressure of pure liquids A and B are 350 and 750 mm Hg respectively at the same temperature. If $\mathrm{x}_{\mathrm{A}}$ and $x_{B}$ are the mole fraction of $A$ and $B$ in solution while $y_{A}$ and $y_{B}$ are the mole fraction of $A$ and $B$ in vapour phase then :

A
$\frac{x_{A}}{x_{B}}<\frac{y_{A}}{y_{B}}$
B
$\frac{x_{A}}{x_{B}}=\frac{y_{A}}{y_{B}}$
C
$\frac{x_{A}}{x_{B}}>\frac{y_{A}}{y_{B}}$
D
$\left(\mathrm{x}_{\mathrm{A}}-\mathrm{y}_{\mathrm{A}}\right)<\left(\mathrm{x}_{\mathrm{B}}-\mathrm{y}_{\mathrm{B}}\right)$

Answer

C. $\frac{x_{A}}{x_{B}}>\frac{y_{A}}{y_{B}}$
$\mathrm{P}_{\mathrm{A}}^{\mathrm{o}}<\mathrm{P}_{\mathrm{B}}^{0}$
$\frac{\mathrm{P}_{\mathrm{A}}^{\mathrm{o}}}{\mathrm{P}_{\mathrm{B}}^{\mathrm{o}}}<1$
$\frac{\mathrm{y}_{\mathrm{A}}}{\mathrm{y}_{\mathrm{B}}}=\frac{\mathrm{P}_{\mathrm{A}}^{o}}{\mathrm{P}_{\mathrm{B}}^{o}} \frac{\mathrm{x}_{\mathrm{A}}}{\mathrm{x}_{\mathrm{B}}}$
$\underline{y_{A}}$
$\frac{y_{B}}{x_{A}}<1$
$\mathrm{x}_{\mathrm{B}}$
$\frac{y_{A}}{y_{B}}<\frac{x_{A}}{x_{B}}$

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MCQ 134 Marks

The correct statement amongst the following is :

A
The term 'standard state' implies that the temperature is $0^{\circ} \mathrm{C}$
B
The standard state of pure gas is the pure gas at a pressure of 1 bar and temperature 273 K
C
$\Delta_{f} \mathrm{H}_{298}^{\theta}$ is zero for $\mathrm{O}(\mathrm{g})$
D
$\Delta_{\mathrm{f}} \mathrm{H}_{500}^{\theta}$ is zero for $\mathrm{O}_{2}(\mathrm{~g})$

Answer

D. $\Delta_{\mathrm{f}} \mathrm{H}_{500}^{\theta}$ is zero for $\mathrm{O}_{2}(\mathrm{~g})$
For standard state $\Rightarrow$ pressure $=1$ bar and temperature is specified only
$\Rightarrow\left(\Delta \mathrm{H}_{\mathrm{f}}^{\mathrm{o}}\right)_{\mathrm{O}_{2,(\mathrm{~g})}}=0$

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MCQ 144 Marks

Match List-I with List-II

Choose the correct answer from the options given below :

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

Answer

C. (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
Aromatic halide give nucleophilic substitution reaction at high temperature or in presence of $-\mathrm{I} /-$ $M$ group rate of reaction high even at low temperature.
A-IV
B-III
C-II
D-I

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MCQ 154 Marks

Choose the incorrect trend in the atomic radii (r) of the elements :

A
$\mathrm{r}_{\mathrm{Br}} < \mathrm{r}_{\mathrm{K}}$
B
$\mathrm{r}_{\mathrm{Mg}} < \mathrm{r}_{\mathrm{Al}}$
C
$\mathrm{r}_{\mathrm{Rb}} < \mathrm{r}_{\mathrm{CS}}$
D
$\mathrm{r}_{\mathrm{At}} < \mathrm{r}_{\mathrm{Cs}}$

Answer

B. $\mathrm{r}_{\mathrm{Mg}}<\mathrm{r}_{\mathrm{Al}}$
In a period from left to right atomic size decreases.

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MCQ 164 Marks

"P" is an optically active compound with molecular formula $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}$. When " P " is treated with 2,4-dinitrophenylhydrazine, it gives a positive test. However, in presence of Tollens reagent, "P" gives a negative test. Predict the structure of "P".

A
B
C
D

Answer

B.

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MCQ 174 Marks

$\mathrm{A}(\mathrm{g}) \rightarrow \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$ is a first order reaction.

Time	T	$\infty$
$\mathbf{P}_{\text {system }}$	$\mathrm{P}_{\mathrm{t}}$	$\mathrm{P}_{\infty}$

The reaction was started with reactant A only. Which of the following expression is correct for rate constant k ?

A
$k=\frac{1}{t} \ln \frac{2\left(p_{\infty}-P_{t}\right)}{P_{t}}$
B
$k=\frac{1}{t} \ln \frac{p_{\infty}}{P_{t}}$
C
$k=\frac{1}{t} \ln \frac{p_{\infty}}{2\left(p_{\infty}-P_{t}\right)}$
D
$k=\frac{1}{t} \ln \frac{p_{\infty}}{\left(p_{\infty}-P_t\right)}$

Answer

C. $k=\frac{1}{t} \ln \frac{p_{\infty}}{2\left(p_{\infty}-P_{t}\right)}$

$\begin{array}{l}P_t=P^o+x \Rightarrow x=P_t-P^o=P_t-\frac{P_{\infty}}{2} \\ P_{\infty}=2 P^o \Rightarrow P^o=\frac{P_{\infty}}{2} \\ k=\frac{1}{t} \ln \frac{P^o}{P^o-x} \\ k=\frac{1}{t} \ln \frac{P_{\infty}}{2\left(P_{\infty}-P_t\right)}\end{array}$

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MCQ 184 Marks

The hydration energies of $\mathrm{K}^{+}$and $\mathrm{Cl}^{-}$are -x and -y $\mathrm{kJ} / \mathrm{mol}$ respectively. If lattice energy of KCl is -z $\mathrm{kJ} / \mathrm{mol}$, then the heat of solution of KCl is :

A
$+x-y-z$
B
$x+y+z$
C
$z-(x+y)$
D
$-z-(x+y)$

Answer

C. $z-(x+y)$

$\begin{aligned} \Delta H _{\text {Sol }^{ n } .} & = L \cdot E \cdot+( H \cdot E )_{ K _{( g )}^{+}}+( HE )_{ Cl _{( g )}^{-1}} \\ & = Z - x - y \\ & = z -( x + y )\end{aligned}$

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MCQ 194 Marks

Mixture of 1 g each of chlorobenzene, aniline and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel, 5 M NaOH (30 mL ) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains :

A
benzoic acid
B
benzoic acid and aniline
C
benzoic acid and chlorobenzene
D
chlorobenzene and aniline

Answer

D. chlorobenzene and aniline

Organic layer in funnel are mixture of chloro benzene and aniline

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MCQ 204 Marks

Given below are two statements :
Statement (I): On hydrolysis, oligo peptides give rise to fewer number of $\alpha$-amino acids while proteins give rise to a large number of $\beta$-amino acids.
Statement (II) : Natural proteins are denatured by acids which convert the water soluble form of fibrous proteins to their water insoluble form.
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 correct
B
Statement I is incorrect but Statement II is correct
C
Both statement I and statement II are incorrect
D
Statement I is correct but Statement II is incorrect

Answer

C. Both statement I and statement II are incorrect
(i) Protein does not gives $\beta$-amino acid on hydrolysis
(ii) Fibrous protein are not water soluble
So both statement's are wrong

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