M.C.Q (1 Marks)

MCQ 11 Mark

Which of the following methods of preparation of amines will give same number of carbon atoms in the chain of amines as in the reactant?

A
Treatment of amide with bromine in an aqueous solution of sodium hydroxide
B
Heating alkylhalide with potassium salt of phthalimide followed by hydrolysis
C
Reaction of nitrite with $LiAlH_4$
D
Reaction of amide with $LiAlH_4$ followed by treatment with water

Answer

Aliphatic and aryl/alkyl primary amines can be prepared by the reduction of the corresponding nitriles with lithium aluminium hydride $LiAIH_4.$

Heating alkyl halide with primary, secondary, and tertiary amine can be prepared by reduction of $LiAlH_4$ ether followed by treatment with water.

Heating alkyl halide with potassium salt of phthalimide followed by hydrolysis produces primary amine. This process is known as Gabriel's phthalimide reaction. The number of carbon atoms in the chain of amines of the product is the same as a reactant.

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MCQ 21 Mark

The conversion of an alkyl halide into alcohol by aqueous $\ce{NaOH}$ is classified as

A
a dehydrohalogenation reaction
✓
a substitution reaction
C
an addition reaction
D
a dehydration reaction

Answer

Correct option: B.

a substitution reaction

Alkyl halides on alkaline hydrolysis $($aqueous $\ce{NaOH)}$ get converted into alcohol. This takes place by a nucleophilic substitution reaction where the $-X$ atom is substituted by a nucleophile i.e $-OH$ group. The primary alkyl halides undergo nucleophilic substitution reaction by $SN_2$ substitution mechanism, while tertiary alkyl halides follow $SN_1$ substitution mechanism.

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MCQ 31 Mark

Which of the following does not give Cannizaro reaction?

A
$\ce{(CH_3)_3 }\text{C-CHO}$
✓
$\ce{(CH_3)_2 }\text{C-CHO}$
C
$\text{HCHO}$
D

Answer

Correct option: B.

$\ce{(CH_3)_2 }\text{C-CHO}$

$\ce{(CH_3)_2 }\text{C-CHO}$ doesn't give cannizaro reaction.

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MCQ 41 Mark

The half life of a substance in a first order reaction is $15 \ \min$. The rate constant is

✓
$4.62 x 10^{-2} \min^{-1}$
B
$6.74 x 10^{-2} \min^{-1}$
C
$2.46 x 10^2 \min^{-1}$
D
$7.18 x 10^2 \min^{-1}$

Answer

Correct option: A.

$4.62 x 10^{-2} \min^{-1}$

for first order reaction $t_{1 / 2}=\frac{0.693}{k}$
Given:
$t_{1/2}=15 \ t_{1/2}=15 \min$
So,
$k=0.693\ t_{1/2} = 0.69315 = 0.0462 \min−1_k$
$=t_{1/2} \ 0.693=150.693=0.0462 \min−1$
Or, in scientific notation:
$k=4.62\times 10−2 \min−1k=4.62\times 10−2 \min−1$
$4.62 x 10^{-2} \min^{-1}$

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MCQ 51 Mark

The incorrect statement about interstitial compounds is:

A
They retain metallic conductivity.
B
They are very hard.
✓
They are chemically reactive.
D
They have high melting point.

Answer

Correct option: C.

They are chemically reactive.

(c) They are chemically reactive.
Explanation: Interstitial compounds are obtained when small atoms like H, B, C, resemble N, etc. fit into the lattice of other elements. They are chemically inert

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MCQ 61 Mark

Chlorine reacts with cold and dilute $\ce{NaOH}$ to give

A
$\ce{NaCIO}$ and $\ce{NaCIO_3}$
B
$\ce{NaCl}$ and $\ce{NaCIO_3}$
✓
$\ce{NaCl}$ and $\ce{NaCIO}$
D
$\ce{NaCl}$ and $\ce{NaCIO_4}$

Answer

Correct option: C.

$\ce{NaCl}$ and $\ce{NaCIO}$

Chlorine reacts with cold and dilute $\ce{NaOH}$ to produce a mixture of sodium chloride $\ce{(NaCl)}$ and sodium hypochloride $\ce{(NaOCl). 2NaOH + Cl_2 \rightarrow NaCl + NaOCl + H_2O}$

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MCQ 71 Mark

Match the items given in column I with that in column II.

Column I	Column II
(a) Molarity	(1) $\frac{\text { Mass of solute }}{\text { Mass of solution }} \times 10^6$
(b) Molality	(2) Number of gram moles of a solute per litre of solution
(c)Normality	(3) Number of gram moles of a solute per kg of solvent
(d) ppm	iv) Number of gram equivalent of a solute per litre of solution

✓
(a) (2), (b) - (3), (c) - (4), (d) - (1)
B
(a) (4), (b) - (3), (c) - (2), (d) - (1)
C
(a)-(3), (b) - (2), (c) - (1), (d) - (4)
D
(a)-(1), (b) - (2), (c) - (3), (d) - (4)

Answer

Correct option: A.

(a) (2), (b) - (3), (c) - (4), (d) - (1)

(a) (a)-(2), (b) - (3), (c) - (4), (d) - (1)
Explanation: (a) - (2), (b) - (3), (c) - (4), (d) - (1)

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MCQ 81 Mark

The ionic reactions are generally very fast because

✓
It does not involve bond breaking
B
The number of collisions between ions are very large
C
Reactions are highly exothermic
D
The energy of interaction between charged ion is greater than between neutral molecules

Answer

Correct option: A.

It does not involve bond breaking

(a) It does not involve bond breaking
Explanation: Ionic reactions do not involve bond breaking, energy is directly used in completing the reaction, therefore they are fast.

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MCQ 91 Mark

A compound $(A)$ with molecular formula $\ce{C_5H_{10}O},$ forms a phenyl hydrazone and gives negative Tollens' and iodoform tests. The compound on reduction gives $n-$pentane. The compound $(A)$ is:

✓
Pentan$-3-$one
B
Pentan$-2-$one
C
Pentanal
D
Pentanol

Answer

Correct option: A.

Pentan$-3-$one

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MCQ 101 Mark

Anisole can be prepared by the action of methyl iodide on sodium phenate. The reaction is called

A
Fittigs reaction
B
Wurtzs reaction
✓
Williamsons reaction
D
Etards reaction

Answer

Correct option: C.

Williamsons reaction

(c) Williamsons reaction
Explanation: The reaction of an alkyl halide with sodium alkoxide to give ether (alkoxy alkane), is known as Williamson's synthesis. In this reaction, an ether (anisole) is prepared by the action of alkyl halide (methyl iodide) on sodium alkoxide (sodium phenate), so it is an example of Williamson's synthesis.

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MCQ 111 Mark

β-pleated sheet structure in proteins refers to

A
tertiary structure
B
primary structure
C
quaternary structure
✓
secondary structure

Answer

Correct option: D.

secondary structure

(d) secondary structure
Explanation: Alpha helices and beta sheets are the two most known secondary structures of protein, As the protein folds into a three-dimensional structure, the secondary structure forms an intermediate.

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MCQ 121 Mark

Which one of the following compounds is more reactive towards $S_N1$ reaction?

A
$C_6H_5CH(C_6H_5)Br$
B
$CH_2=CHCH_2Br$
C
$C_6H_5CH(CH_3)Br$
D
$C_6H_5CH_2Br$

Answer

$C_6H_5CH(C_6H_5)^+$ carbocation formed is more stable.

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Chemistry M.C.Q (1 Marks)

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