M.C.Q (1 Marks)

MCQ 1011 Mark

Carbon has no tendency to form complex compounds due to:

A
Its small size.
B
The availability of vacant $d-$orbitals.
✓
Non$-$availability of vacant $d-$orbitals.
D
No tendency to form covalent bonds.

Answer

Correct option: C.

Non$-$availability of vacant $d-$orbitals.

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MCQ 1021 Mark

The most commonly used reducing agent is:

A
$\mathrm{AlCl}_3$
B
$\mathrm{PbCl}_2$.
C
$\mathrm{SnCl}_4$.
✓
$\mathrm{SnCl}_2$

Answer

Correct option: D.

$\mathrm{SnCl}_2$

$+4$ oxidation state of $Sn$ is more stable than $+2$ oxidation state. Therefore, $\ce{Sn^{2+}}$ can be easily oxidised to $\ce{Sn^{4+}}$ and hence $\ce{SnCl_2}$ acts a reducing agent.
$\text{SnCl}_2+2\text{Cl}\rightarrow\text{SnCl}_4+2\text{e}^-$

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MCQ 1031 Mark

Which of the following statements is incorrect?

A
Aluminium is a bright silvery$-$white metal.
B
Aluminium forms alloys with $\text{Cu, Mn, Mg, Si}$ and $\text{Zn.}$
✓
The use of aluminium and its compounds for domestic purposes is now increased considerably.
D
Both $(a)$ and $(b).$

Answer

Correct option: C.

The use of aluminium and its compounds for domestic purposes is now increased considerably.

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MCQ 1041 Mark

Which of the following is used to convert alcohol to petroleum directly?

✓
$\text{ZSM}-5$
B
$\text{Fe}_2\text{O}_3$
C
$\text{Cr}_2\text{O}_3/ \text{Al}_2\text{O}_3$
D
Feldspar

Answer

Correct option: A.

$\text{ZSM}-5$

$\text{Alcohol}\xrightarrow{\text{ZSM-5}}\text{Petroleum}$

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MCQ 1051 Mark

Oxidation of aluminium is:

✓
Reversible
B
Exothermic
C
Endothermic
D
Slow reaction

Answer

Correct option: A.

Reversible

$Al$ has a strong affinity for $O_2$. Oxidation of $Al$ is a reaction of negative enthalpy$($exothermic$)$.

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MCQ 1061 Mark

Borax bead test is not used to identify cation in:

A
Cobalt salt
B
Nickel salt
✓
Aluminium salt
D
Copper salt

Answer

Correct option: C.

Aluminium salt

Aluminium forms colourless metaborate and thus gives an indecisive test.

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MCQ 1071 Mark

Which one of the following is the correct statement?

A
Beryllium exhibits coordination number of six
✓
Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase
C
$\mathrm{B}_2 \mathrm{H}_6 \cdot 2 \mathrm{NH}_3$ is known as 'inorganic benzene'
D
Boric acid is a protonic acid

Answer

Correct option: B.

Chlorides of both beryllium and aluminium have bridged chloride structures in solid phase

$Be$ and $Al$ are diagonally related with each other and chlorides of both beryllium and aluminium have bridged chloride structures in the solid phase.

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MCQ 1081 Mark

Most covalent halide of aluminium is:

A
Aluminium bromide
B
Aluminium fluoride
✓
Aluminium iodide
D
Aluminium chloride

Answer

Correct option: C.

Aluminium iodide

Due to higher polarisibility, iodide is most covalent by Fajan's rule.

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MCQ 1091 Mark

Boron compounds behave as Lewis acids because of their :

A
Acidic nature.
B
Covalent nature.
C
Ionic nature.
✓
Vacant orbital.

Answer

Correct option: D.

Vacant orbital.

A Lewis acid is an electron pair acceptor, while Lewis base is an electron pair donor.
Boron compounds behave as Lewis acids because of their vacant orbital. Its octet is incomplete, in which boron can accept an electron pair.

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MCQ 1101 Mark

Self protective metal among the following is:

A
$Na$
✓
$Al$
C
$Fe$
D
$K$

Answer

Correct option: B.

$Al$

$Al$ when comes in contact with air to form $\mathrm{Al}_2 \mathrm{O}_3$ which forms a protective passive layer on the metal. This layer cannot be removed by chemical means.

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MCQ 1111 Mark

The material used in solar cell contains :

A
$Cs$
✓
$Si$
C
$Sn$
D
$T$

Answer

Correct option: B.

$Si$

Silicon is a semicoductor and is used in solar cells, sometimes doped.

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MCQ 1121 Mark

Boric acid is acid because its molecule:

A
Contamp replaceable $H^+$.
B
Gives up proton.
✓
Accepts $\ce{OH^-}$ from water and releases proton.
D
Combines with proton from water molecule.

Answer

Correct option: C.

Accepts $\ce{OH^-}$ from water and releases proton.

$\text{B(OG})_4+\text{H}_2\text{O}\rightarrow\text{B(OH)}^-_4+\text{H}^+$

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MCQ 1131 Mark

A orange solid $'X'$ on heating gives green reside, a gas non$-$supporter of combustion and water. Identify $X$ :

✓
$\left(\mathrm{NH}_4\right)_2 \mathrm{Cr}_2 \mathrm{O}_7$
B
$\mathrm{CaCO}_3$
C
$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7 $
D
$\mathrm{KMnO}_4$

Answer

Correct option: A.

$\left(\mathrm{NH}_4\right)_2 \mathrm{Cr}_2 \mathrm{O}_7$

$(\text{NH}_4)_2\text{Cr}_2\text{O}_7\xrightarrow{\ \ \ \text{o}\ \ \ }\text{N}_2+4\text{H}_2\text{O}+\text{Cr}_2\text{O}_3\\ \ \ \ \ \ \ \ ^\text{(orange)}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ^\text{(green)}$

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MCQ 1141 Mark

Aqueous solution of borax is $.........$ in nature:

A
Neutral
B
Acidic
✓
Alkaline
D
None

Answer

Correct option: C.

Alkaline

The aqueous solution is alkaline due to hydrolysis resulting into the formation of strong base $\ce{NaOH}$ and weak acid tetraboric acid.

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MCQ 1151 Mark

Quartz is extensively used as a piezoelectric material, it contains $.........$

A
$Pb.$
✓
$Si.$
C
$Ti.$
D
$Sn.$

Answer

Correct option: B.

$Si.$

Quartz is one of the crystalline from of silica and at high temprature can be converted into other crystalline forms. It is extensively used as apiezoelectric material.

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MCQ 1161 Mark

The oxidation state of the most electronegative element in the products of the reaction $\ce{BaO_2}$ with $\ce{H_2SO_4}$ are :

A
$0$ and $-1$
B
$-2$ and $+1$
✓
$-1$ and $-2$
D
$-2$ and $0$

Answer

Correct option: C.

$-1$ and $-2$

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MCQ 1171 Mark

The basic structural units of silicates is:

✓
$\text{SiO}^{2-}_3$
B
$\text{SiO}^{2-}_4$
C
$\text{SiO}^-$
D
$\text{SiO}^{4-}_4$

Answer

Correct option: A.

$\text{SiO}^{2-}_3$

$\text{SiO}^{4-}_4$ is basic structural unit of silicates.

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MCQ 1181 Mark

Boron forms $\text{BX3}$ type of halides. The correct decreasing order of Lewis$-$acid strength of these halides is:

A
$ \mathrm{BF}_3>\mathrm{BCl}_3>\mathrm{BBr}_3>\mathrm{BI}_3 $
✓
$ \mathrm{BI}_3>\mathrm{BBr}_3>\mathrm{BCl}_3>\mathrm{BF}_3 $
C
$ \mathrm{BF}_3>\mathrm{BI}_3>\mathrm{BCl}_3>\mathrm{BBr}_3 $
D
$ \mathrm{BF}_3>\mathrm{BCl}_3>\mathrm{BI}_3>\mathrm{BBr}_3 $

Answer

Correct option: B.

$ \mathrm{BI}_3>\mathrm{BBr}_3>\mathrm{BCl}_3>\mathrm{BF}_3 $

The decreasing order of the Lewis acidity of boron halides is $\mathrm{BI}_3>\mathrm{BBr}_3>\mathrm{BCl}_3>\mathrm{BF}_3 $.
This order is due to the relative tendency of the halogen atom to back donate its unutilized electrons to the vacant p-orbitals of boron atom.
Due to the back donation of electrons from fluorine to boron, the electron deficiency of boron is reduced and hence, Lewis acidity is decreased.
The tendency for the formation of back bonding is maximum in boron trifluoride and decreases very rapidly from boron trifluoride to boron triodide.

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MCQ 1191 Mark

Which of the following does not exist ?

A
$\ce{BiCl_5}$
B
$\ce{XeH_4}$
C
$\ce{BiF_5}$
✓
Both $(A)$ and $(B)$

Answer

Correct option: D.

Both $(A)$ and $(B)$

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MCQ 1201 Mark

Following are the figures of two different allotropes of carbon. Identify these allotropes from the following options.

A
$A \rightarrow$ Graphite; $B \rightarrow$ Diamond.
✓
$A \rightarrow$ Diamond; $B \rightarrow$ Graphite.
C
$A \rightarrow$ Graphite; $B \rightarrow$ Fullerene.
D
$A \rightarrow$ Diamond; $B \rightarrow$ Fullerene.

Answer

Correct option: B.

$A \rightarrow$ Diamond; $B \rightarrow$ Graphite.

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MCQ 1211 Mark

The maxium covalency of aluminium is:

A
$4$
✓
$6$
C
$8$
D
$3$

Answer

Correct option: B.

$6$

The maximum covalency of Aluminium is $6$. Since Aluminium belongs to the $3^{rd}$ period, it possesses a $3d$ subshell as well. As a cation it can use $\ce{sp^3d^2}$ hybrid orbitals for a covalency of $6$.

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MCQ 1221 Mark

Crystalline boron in small amounts may be obtained by :

A
Reducing $\mathrm{BCl}_3$ with $\mathrm{H}_2$
B
pyrolysis of $\mathrm{BI}_3$
C
thermal decomposition of diborane
✓
all of these

Answer

Correct option: D.

all of these

Crystalline boron is obtained by reducing volatile boron halides with hydrogen at high temperatures. Ultrapure boron for use in semiconductor industry is produced by the decomposition of diborane at high temperature and then purified with the zone melting process.

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MCQ 1231 Mark

Aluminium oxide is not reduced by chemical reactions since :

A
Aluminium oxide is reactive.
B
Reducing agent contaminate
✓
Aluminium oxide is highly stable
D
Process polutes the environment.

Answer

Correct option: C.

Aluminium oxide is highly stable

Aluminium oxide is not reduced by chemical reactions since aluminium oxide is most stable and it does not gain electrons from any reducing agent.

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MCQ 1241 Mark

An element $R$ belongs to $\text{III A}$ group. Which is true with respect to $R$?

A
It is a gas at room temperature
B
It has an oxidation state of $+4$
✓
It forms an oxide of the type $\mathrm{R}_2 \mathrm{O}_3$
D
It forms a halide of the type $\mathrm{Rx}_2$

Answer

Correct option: C.

It forms an oxide of the type $\mathrm{R}_2 \mathrm{O}_3$

An $\text{III A}$ group element has valency $3$.
So they form an oxide of type $\mathrm{R}_2 \mathrm{O}_3$.

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MCQ 1251 Mark

The color imparted by $\text{Co(Il)}$ compounds to glass is:

✓
Deep blue.
B
Green.
C
Yellow.
D
Red.

Answer

Correct option: A.

Deep blue.

Cobalt primarily used as the metal, in the preparation of magnetic, wear$-$resistant and high$-$strength alloys.
The color imparted by $\text{Co(Il)}$ compounds to glass is deep blue.

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MCQ 1261 Mark

Which of the following is not correct ?

A
Anhydrous $\mathrm{AlCl}_3$ exists as $\mathrm{Al}_2 \mathrm{Cl}_6$
B
Anhydrous $\mathrm{AlCl}_3$ sublimes on heating
C
Anhydrous $\mathrm{AlCl}_3$ fumes in air
✓
Anhydrous $\mathrm{AlCl}_3$ is ionic

Answer

Correct option: D.

Anhydrous $\mathrm{AlCl}_3$ is ionic

All statements are correct except that $\mathrm{AlCl}_3$ is covalent in anhydrous form and its aqueous solution is ionic in nature.

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MCQ 1271 Mark

Silicon is the $.........$ abundant element in the earth's crust:

A
most
✓
$2^{nd}$ most
C
$3^{rd}$ most
D
none of these

Answer

Correct option: B.

$2^{nd}$ most

Silicon is the second $(27.7\%$ by mass$)$ most abundant element in the earth's crust.

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MCQ 1281 Mark

Which of the element shows $+4$ oxidation state?

✓
$Sn$
B
$Ra$
C
$Fr$
D
$Sc$

Answer

Correct option: A.

$Sn$

Only tin is capable of exhibiting stable $+4$ oxidation state while others cannot. $\mathrm{Sn}^{+4}$ state is stable and forms $\mathrm{SnCl}_4$ compound.

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MCQ 1291 Mark

Which of these forms nitride with nitrogen at higher temperature?

A
Aluminium
B
Boron
✓
Both $A$ and $B$
D
Indium

Answer

Correct option: C.

Both $A$ and $B$

Aluminium and boron forms nitride with nitrogen at higher temperature due to the high bond energy of nitrogen. In case of aluminium, a thin oxide layer is formed so it also needs high temperature to react with nitrogen to form the nitride.

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MCQ 1301 Mark

An element $'X'$ atomic number $51$ belongs to $.........$

A
$S-$block
✓
$P-$block
C
$D-$block
D
$F-$block

Answer

Correct option: B.

$P-$block

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MCQ 1311 Mark

The form of $\mathrm{SiO}_2$ used as piezoelectric material:

A
Cristobalite
✓
Quartz
C
Kiesulguhr
D
Silica gel

Answer

Correct option: B.

Quartz

Quartz crystals have piezoelectric properties; they develop an electric potential upon the application of mechanical stress. An early use of this property of quartz crystals was in phonograph pickups. One of the most common piezoelectric uses of quartz today is as a crystal oscillator. The quartz clock is a familiar device using the mineral. The resonant frequency of a quartz crystal oscillator is changed by mechanically loading it, and this principle is used for very accurate measurements of very small mass changes in the quartz crystal microbalance and in thin film monitors.

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MCQ 1321 Mark

Why $\mathrm{Bi}^{3+}$ more stable than $\mathrm{Bi}^{+5}$ ?

✓
Due to inert pair effect
B
Due to inert gas electronic configuration
C
Due to half filled configuration
D
Due to lanthanide Contraction

Answer

Correct option: A.

Due to inert pair effect

$\mathrm{Bi}^{3+}$is more stable than $\ce{Bi^{5+}}$ due to inert pair effect. Ongoing down the group, inert pair effect increases due to more penetration of $s-$ orbital in nucleus due to which element tends to show lower oxidation state more stable than higher oxidation state. Thus, bismuth will show a strong tendency to change into $+3$ state from $+5$ state.

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MCQ 1331 Mark

Which of the following forms vortex ring?

✓
$\mathrm{P}_2 \mathrm{O}_5$
B
$ \mathrm{PH}_3 $
C
$ \mathrm{NH}_3$
D
$ \mathrm{P}_2 \mathrm{O}_{10}$

Answer

Correct option: A.

$\mathrm{P}_2 \mathrm{O}_5$

Phosphine forms vortex rings of $\mathrm{P}_2 \mathrm{O}_5$ when it comes in contact of air. These rings are in form of white smoke.
$\therefore$ They are used in making smoke screens in warfare.

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MCQ 1341 Mark

Which is the crystalline form of silica?

A
Agate
B
Jaspar
C
Onyx
✓
Crystobalite

Answer

Correct option: D.

Crystobalite

Silica $\ce{(SiO_2)}$ occurs in various crystallographic forms such as quartz, crystobalite and tridymite that are interconvertible at suitable temperatures.

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MCQ 1351 Mark

Aqueous tension is the vapour pressure of water and depends only upon temperature: If the statement is true enter $1$, else enter $0$ :

✓
$1$
B
$0$
C
Both $A$ and $B$
D
None of these

Answer

Correct option: A.

$1$

Aqueous tension is defined as the partial pressure of the water vapour present in the moist gas. Aqueous pressure exerted by a gas at particular temperature and it depends upon temperature.
The pressure exerted by moist gas $=$ pressure exerted by dry gas $+$ pressure of water vapour $($aqueous tension$)$.

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MCQ 1361 Mark

The relationship between first, second and third ionisation enthalpies of each group$-13$ element is:

A
$\Delta_\text{i}\text{H}_\text{1}>\Delta_\text{i}\text{H}_2>\Delta_\text{i}\text{H}_3$
✓
$\Delta_\text{i}\text{H}_\text{1}<\Delta_\text{i}\text{H}_2<\Delta_\text{i}\text{H}_3$
C
$\Delta_\text{i}\text{H}_1=\Delta_\text{i}\text{H}_2=\Delta_\text{i}\text{H}_3$
D
$\Delta_\text{i}\text{H}_3<\Delta_\text{i}\text{H}_1<\Delta_\text{i}\text{H}_2$

Answer

Correct option: B.

$\Delta_\text{i}\text{H}_\text{1}<\Delta_\text{i}\text{H}_2<\Delta_\text{i}\text{H}_3$

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MCQ 1371 Mark

$\ce{BF_3}$ easily reacts with Lewis base such as $\ce{NH_3}$ to complete octet around boron. This can be expressed as:

✓
$\text{F}_3\text{B}\ +:\text{NH}_{3} \xrightarrow{\ \ \ \ \ }\text{F}_3\text{B}\leftarrow\text{NH}_3$
B
$\text{F}_3\text{B}+:\text{NH}_3\xrightarrow{\ \ \ \ \ }\text{F} _3\text{B}\rightarrow\text{NH}_3$
C
$:\text{BF}_3+\text{NH}_3\xrightarrow{\ \ \ \ \ \ \ \ }\text{BF}_3\rightarrow\text{NH}_3$
D
$:\text{BF}_3+\text{NH}_3\xrightarrow{\ \ \ \ \ \ \ }\text{BF}_3\leftarrow\text{NH}_3$

Answer

Correct option: A.

$\text{F}_3\text{B}\ +:\text{NH}_{3} \xrightarrow{\ \ \ \ \ }\text{F}_3\text{B}\leftarrow\text{NH}_3$

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MCQ 1381 Mark

At standard conditions $.........$ has an allotropic form that is a good electrical conductor:

✓
Carbon
B
Nitrogen
C
Neon
D
Argon

Answer

Correct option: A.

Carbon

Carbon has an allotrope known as Graphite. Graphite is a very good conductor of electricity. It can conduct electricity due to the presence of delocalized free electron.

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MCQ 1391 Mark

Which of the following is used to make transistor and semiconductor devices?

A
Ultrapure form of germanium.
B
Ultrapure form of silicon.
✓
Both $(a)$ and $(b)$.
D
Neither $(a)$ nor $(b)$.

Answer

Correct option: C.

Both $(a)$ and $(b)$.

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MCQ 1401 Mark

Halides of $\ce{III A}$ group elements predominantly act as :

A
Lewis bases
✓
Lewis acids
C
Arrhenius acids
D
Neutral halides

Answer

Correct option: B.

Lewis acids

In a trivalent state, the number of electrons around the central atom in a molecule of the compounds of these elements will be only six. Such electron deficient molecules have a tendency to accept a pair of electrons to achieve octet and thus behave as Lewis acids.

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MCQ 1411 Mark

Pnicogens are the elements of group:

✓
$15$
B
$13$
C
$\text{VIII}$
D
Zero

Answer

Correct option: A.

$15$

Members of group $15$ or $VA$ of Periodic Table are called pnicogens. They include $\text{N, P, As, Sb}$ and $\text{Bi}.$

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MCQ 1421 Mark

Boric acid is polymeric due to:

A
Its acidic nature.
✓
The presence of hydrogen bonds.
C
Its monobasic nature.
D
Its geometry.

Answer

Correct option: B.

The presence of hydrogen bonds.

Boric acid is polymeric because of the presence of hydrogen bonds. In the given figure, the dotted lines represent hydrogen bonds.

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MCQ 1431 Mark

$\ce{AlH_3}$ is an example for:

A
interstitial hydride
B
electron rich hydride
C
ionic hydride
✓
electron deficient hydride

Answer

Correct option: D.

electron deficient hydride

According to the Bohr's octet rule, each element tends to completely fill its outermost orbit with $8$ electrons in it. Electronic configuration of aluminium is $2, 8, 3$ that means it still needs $5$ more electrons to complete its octet. That's why aluminium is electron deficient.

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MCQ 1441 Mark

Thermodynamically the most stable form of carbon is:

A
Diamond.
✓
Graphite.
C
Fullerenes.
D
Coal.

Answer

Correct option: B.

Graphite.

Graphite is thermodynamically the most stable form of carbon.

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MCQ 1451 Mark

Quartz is the form ?

A
$ \mathrm{CO}_2$
✓
$ \mathrm{SiO}_2$
C
$\mathrm{SO}_2 $
D
$ \mathrm{NO}_2 $

Answer

Correct option: B.

$ \mathrm{SiO}_2$

Silica is found in many crystalline and amorphous forms.
Quartz is a crystalline form of silica.

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MCQ 1461 Mark

Silicon has a strong tendency to form polymers like silicones. The chain length of silicone polymer can be controlled by adding.

A
$\mathrm{MeSiCl}_3$.
B
$\mathrm{Me}_2 \mathrm{SiCl}_2$.
✓
$\mathrm{Me}_3 \mathrm{SiCl}$.
D
$\mathrm{Me}_4 \mathrm{Si}$.

Answer

Correct option: C.

$\mathrm{Me}_3 \mathrm{SiCl}$.

The chain length of the polymer can be controlled by adding $\ce{(CH_3)_3 SiCl}$ which blocks the end as shown below:

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MCQ 1471 Mark

The mixture of $CO$ and $H$, is known as:

A
Producer gas.
B
Synthesis gas.
C
Water gas.
✓
Both $(b)$ and $(c).$

Answer

Correct option: D.

Both $(b)$ and $(c).$

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MCQ 1481 Mark

The number of possible isomers for disubstituted borazine, $\mathrm{B}_3 \mathrm{N}_3 \mathrm{H}_4 \mathrm{X}_2$ is:

A
$3$
✓
$4$
C
$6$
D
$2$

Answer

Correct option: B.

$4$

The number of possible isomers of distributed borazine is $4$ because of $4$ reactive hydrogen ions.

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MCQ 1491 Mark

Aluminium exist in $+3$ state where as thallium exist in both $+1\ \&+3$ oxidation state. Reason for this is

✓
inert pair effect
B
Lanthanoid contraction
C
Diagonal relationship
D
none of these

Answer

Correct option: A.

inert pair effect

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MCQ 1501 Mark

Which metal powder suspended in oil is used as a paint for mirrors?

A
$Fe$
B
$Sn$
C
$Ag$
✓
$Al$

Answer

Correct option: D.

$Al$

The reflective property of aluminium is being used here. Powdered aluminium suspended in oil is used as paint. The low cost and easy availability make it useful in this.
This compound is also known as Diaspore having formula $\mathrm{Al}_2 \mathrm{O}_3 \cdot \mathrm{H}_2 \mathrm{O}$.

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Chemistry M.C.Q (1 Marks)