M.C.Q (1 Marks)

MCQ 11 Mark

In order to prepare a $1^\circ$ amine from an alkyl halide with simultaneous addition of one $\ce{CH_2}$ group in the carbon chain, the reagent used as source of nitrogen is$..........$

A
Sodium amide, $\ce{NaNH_2}$
✓
Sodium azide, $\ce{NaN_3}$
C
Potassium phthalimide, $\ce{C_6H_4(CO)_2 N^{-} K ^{+}}$
D
Ethanolic $\ce{NaCN}$

Answer

Correct option: B.

Sodium azide, $\ce{NaN_3}$

$ \text{KCN}$ is used to increase the number of carbon atoms.
$\ce{RX + NaCN} \rightarrow \ce{RCN + KX}$
$\ce{R-CN + 4 H} \xrightarrow{H_2 / \text { Raney } N i} \ce{RCH_2NH_2}$

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MCQ 21 Mark

Monochlorination of toluene in sunlight followed by hydrolysis by aq. NaOH yields

✓
benzyl alcohol
B
o-cresol
C
2,4-dihydroxytoluene
D
m-cresol

Answer

Correct option: A.

benzyl alcohol

(a) benzyl alcohol
Explanation: Monochlorination of toluene gives benzylchloride.
$
C_6 H_5 CH_3+Cl_2+hv \rightarrow C_6 H_5 CH_2 Cl
$
benzyl chloride on reaction with aq. NaOH will give benzyl alcohol by substitution reaction.
$
C_6 H_5 CH_2 Cl+NaOH(aq) \rightarrow C_6 H_5 CH_2 OH
$

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MCQ 31 Mark

Methyl ketones are usually characterized by:

A
Benedict's reagent
✓
Iodoform test
C
Schiff's test
D
Tollen's reagent

Answer

Correct option: B.

Iodoform test

(b) Iodoform test
Explanation: $CH _3 COR + I _2+ NaOH \rightarrow CHI _3+ RCOO ^{-} Na ^{+}$
Iodoform test is a characteristic test given by methyl ketones. CHI formed is yellow precipitate.

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MCQ 41 Mark

In a chemical reaction X → Y, it is found that the rate of reaction doubles when the concentration of X is increased four times. The order of the reaction with respect to X is

✓
$\frac{1}{2}$
B
2
C
1
D
0

Answer

Correct option: A.

$\frac{1}{2}$

(a) $\frac{1}{2}$
Explanation: $X \rightarrow Y$
Rate $( r ) \propto[ X ]^{ n }$ [Where $n =$ order of reaction $]$
If the concentration X is increased by 4 times
$
X^{\prime}=4 X
$
Then, Rate $\left(r^{\prime}\right) \propto\left[X^{\prime}\right]^{ n }$
$
\frac{r^{\prime}}{r}=\frac{[4 X]^n}{[X]^n}=2
$
$r^{\prime}$ is new rate, $X^{\prime}$ is a new concentration
$
\begin{aligned}
{[4]^{n} } & =2 \\
n & =\frac{1}{2}
\end{aligned}
$
Order of reaction $=\frac{1}{2}$

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MCQ 51 Mark

Which of the following characteristics of transition metals is associated with their catalytic activity?

A
Paramagnetic nature
B
High enthalpy of atomisation
✓
Variable oxidation states
D
Colour of hydrated ions

Answer

Correct option: C.

Variable oxidation states

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MCQ 61 Mark

Decomposition of benzene diozonium chloride by using $\ce{Cu_2Cl_2/HCl}$ to form chlorobenzene is:

A
Wurtz $-$ Fittig reaction
B
Friedel $-$ Crafts reaction
✓
Sandmeyer's reaction
D
Finkelstein reaction

Answer

Correct option: C.

Sandmeyer's reaction

$\ce{C_6H_5N_2^{+}Cl^{-} + Cu_2Cl_2 / HCl} \rightarrow \ce{C_6H_5Cl}$
Mixing the solution of the freshly prepared diazonium salt with cuprous chloride or cuprous bromide results in the replacement of the diazonium group by $- Cl $ or $-Br.$ This is called Sandmeyer's reaction.

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MCQ 71 Mark

Match the items of column $I$ with appropriate entries of column $II.$

Column $I$	Column $II$
$(a)$ For electrolyte $CaSO_4$	$(i) \ i = 5$
$(b)$ For ideal Solution	$(ii) \ i = 2$
$(c)$ For electrolyte $Al_2(SO_4)_3$	$(iii) \ i = 4$
$(d)$ For electrolyte $Na_3PO_4$	$(iv) \ i = 1$

A
$ \text{(a) (iv), (b) - (i), (c) - (ii), (d) - (iii).}$
B
$ \text{(a) (i), (b) - (ii), (c) - (iii), (d) - (iv).}$
C
$ \text{(a) (iii), (b) - (ii), (c) - (iv), (d) - (i).}$
✓
$ \text{(a) (ii), (b) - (iv), (c) - (i), (d) - (iii).}$

Answer

Correct option: D.

$ \text{(a) (ii), (b) - (iv), (c) - (i), (d) - (iii).}$

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MCQ 81 Mark

Consider the reaction
$
N_2(g)+3 H_2(g) \rightarrow 2 NH_3(g)
$
The equality relation between $\frac{d\left[ NH _3\right]}{d t}$ and $\frac{-d\left[ H _2\right]}{d t}$ is:

A
$\frac{d\left[ NH _3\right]}{d t}=-\frac{1}{3} \frac{d\left[ H _2\right]}{d t}$
✓
$\frac{d\left[ NH _3\right]}{d t}=-\frac{2}{3} \frac{d\left[ H _2\right]}{d t}$
C
$\frac{d\left[N H_3\right]}{d t}=-\frac{3}{2} \frac{d\left[H_2\right]}{d t}$
D
$\frac{d\left[ NH _3\right]}{d t}=-\frac{d\left[ H _2\right]}{d t}$

Answer

Correct option: B.

$\frac{d\left[ NH _3\right]}{d t}=-\frac{2}{3} \frac{d\left[ H _2\right]}{d t}$

(b) $\frac{d\left[ NH _3\right]}{d t}=-\frac{2}{3} \frac{d\left[ H _2\right]}{d t}$
Explanation: For the given reaction,
$
\text { rate }=-\frac{1}{2} \frac{d\left[N_2\right]}{d t}=-\frac{1}{3} \frac{d\left[H_2\right]}{d t}=\frac{1}{2} \frac{d\left[N H_3\right]}{d t}
$

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MCQ 91 Mark

Which of the following has most acidic hydrogen?

A
$2, 3 -$Hexanedione
B
$2, 5-$Hexanedione
✓
$2, 4 -$Hexanedione
D
$3 -$Hexanone

Answer

Correct option: C.

$2, 4 -$Hexanedione

$ 2,4-$hexanedione will have active methylene group.
The structure of $2,4-$hexanedione is

$-CH_2$ group present between the two carbonyl group is active methylene group, these hydrogens are highly acidic as their conjugate base is highly stable.

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MCQ 101 Mark

Phenol on distillation with zinc dust gives

A
benzaldehyde
B
benzophenone
✓
benzene
D
benzonic acid

Answer

Correct option: C.

benzene

(c) benzene
Explanation: Phenol is reduced to benzene when it is distilled with zinc dust or its vapour is passed over granules of zinc at 400°C.

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MCQ 111 Mark

In disaccharides, if the reducing groups of monosaccharides i.e. aldehydic or ketonic groups are bonded, these are non$-$reducing sugars. Which of the following disaccharide is a non$-$reducing sugar?

Answer

This structure represents sucrose$($diasaccharides$)$ in which $\alpha-D$ glucose and $\beta-D-$fructose is attached to each other by $C_1-C_2$ glycosidic linkage. Since reducing groups of glucose and fructose are involved in glycosidic bond formation, this is considered as a non$-$reducing sugar.

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MCQ 121 Mark

A halogen used in potential blood substitutes in surgery is:

✓
Fluorine
B
Bromine
C
Iodine
D
Chlorine

Answer

Correct option: A.

Fluorine

(a) Fluorine
Explanation: Certain fully fluorinated compounds are being considered as potential blood substitutes in surgery. So fluorine is the element used in these blood substitutes.

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Chemistry M.C.Q (1 Marks)

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