MCQ Questions for Class 11 Engineering Chemistry Some P-Block Elements Quiz 7

Element X has a ground-state valence electron configuration of

$ns^{2}np^{5}$ .
Select the formula of the carbon compound most likely to be formed.

0%
$CX$
0%
$CX_{2}$
0%
$CX_{4}$
0%
$CX_{6}$

Explanation

Element X has a ground-state valence electron configuration of

$ns^{2}np^{5}$ . It will share one electron to complete its octet. Thus, it will form one covalent bond. C atom shares 4 electrons to complete its octet. Hence, C atom forms 4 covalent bonds. Thus, one C atom will combine with 4 X atoms. aThe formula of the carbon compound most likely to be formed is

$CX_{4}$ .

How many electrons can fit in the orbital for which

$n = 3$ and

$l = 1$ ?

0%
10
0%
14
0%
2
0%
6

Explanation

$n= 3$ and

$l= 1$

$\Rightarrow 3p$ orbital so

$3p$ orbital can accommodate 6 electrons.

Which of these non-metals would be most reactive?

0%
$P$
0%
$S$
0%
$Cl$
0%
$He$
0%
$Ne$

The highest concentration of _______ was found in Hartley coal ash.

0%
Lead
0%
Germanium
0%
Antimony
0%
carbon

State true or false:
The tendency of atom to attract shared pair of electrons is known as electron affinity.

0%
True
0%
False

Chemical formula of cassiterite is _____.

0%
$SnO_2$
0%
$Sn{Cl}_2$
0%
$Sn{Cl}_4$
0%
$SnO_4$

Explanation

Cassiterite

$(SnO_2)$ is the only commercially important source of tin.

Borax is an important mineral of :

0%
aluminium
0%
boron
0%
indium
0%
thallium

Explanation

$\begin{array}{l}\text { Borane }=\mathrm{Na}_{2}\left[\mathrm{~B}_{4}\mathrm{O}_{5}(\mathrm{OH})_{4}\right] \cdot 8 \mathrm{H}_{2} \mathrm{O} \\\text { It is the ore of boron .}\end{array}$

Which of the following is a synthetic element?

0%
Boron
0%
Aluminium
0%
Gallium
0%
Ununtrium

Diaspore, germanite and gallite have:

0%
boron
0%
aluminium
0%
gallium
0%
indium

Explanation

They all have gallium metal.
Gallite -

$CuGaS_2$
Diaspore -

$\alpha -AlO(OH)$
Germanite -

${Cu}_{26}{Fe}_4{Ge}_4S_{32}.$

Which of the following has allotropes?

0%
Aluminium
0%
Boron
0%
indium
0%
Thallium

Which among the following is the most abundant element among boron family?

0%
Boron
0%
Aluminium
0%
Gallium
0%
Indium

Boron exhibits anomalous property due to its___________.

0%
extremely small size
0%
high electronegativity
0%
low electronegativity
0%
low covalency

Which of the following occur with zinc in sulfides?

0%
Boron
0%
Aluminium
0%
Thallium
0%
Indium

Which of the following elements forms only covalent bonds with others?

0%
Boron
0%
Aluminium
0%
Indium
0%
Thallium

Which of the following exhibit covalency only upto 4?

0%
Boron
0%
Aluminium
0%
Thallium
0%
Indium

Explanation

Boron exhibit maximum covalency of four e.g.,

${BH_ 4}^{-}$ ion while other members exhibit a maximum covalency of six e.g.,

$[Al{(OH)}_6]^{3-}$ .

Which of the following element shows only

$+3$ oxidation state?

0%
$B$
0%
$Al$
0%
$Ga$
0%
$In$

Explanation

Option

$(A)$ is correct.

Boron shows only

$+3$ oxidation state.

Electronic configuration of boron family is

$ns^2 \:np^1$ . The atoms of these elements have 3 valence electrons, therefore all these elements show maximum of + 3 oxidation state. Boron shows only +3 oxidation state in its compound & other elements also show +1 oxidation state.The stability of the +3 oxidation state decreases on moving down the group.

The +1 oxidation state becomes more stable as we move down to the group from boron to thallium because of inert pair effect.In the case of the last element, after the removal of one electron from

$p$ orbital, the remaining

$ns^2$ are strongly attracted by the nucleus and do not participate in bonding.

Three centered bond is present in which of the following compound of group 13 element?

0%
$NH_3$
0%
$B_2H_6$
0%
$BCl_3$
0%
$AlCl_3$

Explanation

Option

$(B)$ is correct.

Three centered bond is present in diborane,

$B_2H_6$ . It has three-centre 2-electron bonds, two of them to be exact, each one consisting of the two boron atoms and a hydrogen atom sharing two electrons.

$B_2H_6$ has four terminal and two bridging hydrogen atoms.The four terminal hydrogen atoms and two boron atoms lie one plane. Above and below this plane, there are two bridging hydrogen atoms. Each boron atom forms four bonds eventhough it has only three electrons. The terminal

$B-H$ bonds are regular bonds but the bridge

$B-H$ bonds are different. Each bridge hydrogen is bonded to the two boron atoms only by sharing of two electrons. Such covalent bond is called three centre electron pair bond or a multicentre bond or banana bond

Which of the following shows non-metallic character?

0%
$B$
0%
$Al$
0%
$Ga$
0%
$Th$

Explanation

Option

$(A)$ is correct.

$B$ shows non-metallic character while

$Al,Ga,Th$ are metals.

Which of the given element show anomalous behavior with respect to its other group member?

0%
$B$
0%
$Al$
0%
$Ga$
0%
$In$

Explanation

Option

$(A)$ is correct.

$B$ show anomalous behaviour with respect to its other group member due to its extremely low size and high nuclear charge/size ratio, high electronegativity and non-availability of

$d$ - electrons.

Which among the following can show the maximum of four covalencies?

0%
$Al$
0%
$Ga$
0%
$In$
0%
$B$

Explanation

Option

$(D)$ is correct.

Boron shows the maximum of four covalencies as it has only four orbitals in its outermost shell (e.g.

$BH_4^-$ ).Other elements of the group show covalency of even six due to the presence of

$d-$ orbitals in them(e.g.

$[Al(OH)_6]^{3-}$ ).

Oxide of which group 13 element is acidic in nature:

0%
$B$
0%
$Al$
0%
$Ga$
0%
$In$

Explanation

Option

$(A)$ is correct.

Oxide of boron is acidic in nature. Boron is a non-metal and oxides of non-metals acidic in nature.Boron oxide is acidic and reacts with water to form an acid, boric acid. So, it is an acidic oxide.

$B_2O_3 + 3H_2O \rightarrow 2B(OH)_3$

While moving down the group, acidic strength decreases and basic strength increases, thus the acidic character of oxides decreases down the group.

Oxides of other elements of the group are amphoteric and basic in nature.

Halide of which element exist only in monomeric form is/are:

0%
boron
0%
aluminium
0%
both $A$ and $B$
0%
none of the above

Explanation

Option

$(A)$ is correct.

Halides of boron exist only in monomeric form because boron atom is too small to coordinate with large halide ions.The energy released during the formation of the bridge structure is not sufficient for the cleavage of the typical

$p\pi- p\pi$ bond in

$BX_3$ .

Other members of the group exist as dimmers having halogen - bridged structure.

For one of the element various successive ionization enthalpies (in

$kJ$

${mol}^{-1}$ ) are given below:

I.E	${1}^{st}$	${2}^{nd}$	${3}^{rd}$	${4}^{th}$	${5}^{th}$
	$577.5$	$1810$	$2750$	$11,580$	$14,820$

The element is :

0%
$Si$
0%
$P$
0%
$Al$
0%
$Mg$

Explanation

As the fourth ionization energy is exceptionally high it should be a third group element hence it will be

$Al$ .

$III\ A$ group which element shows different behaviour from its other group members:

0%
$Al$
0%
$Ga$
0%
$In$
0%
$B$

Explanation

Option

$(D)$ is correct.

$III\ A$ group, boron shows different behaviour from its other group members due to extremely low size and high nuclear charge/size ratio, high electronegativity and non-availability of

$d$ - electrons.

Which of the following is acidic in nature?

0%
$Be(OH)_2$
0%
$Mg(OH)_2$
0%
$Al(OH)_3$
0%
$B(OH)_3$

Explanation

Option

$(D)$ is correct.

$B(OH)_3$ is acidic in nature while

$Al(OH)_3$ ,

$Be(OH)_2$ are amphoteric and

$Mg(OH)_2$ is basic in nature.

The formula of mineral borax is:

0%
$Na_2B_4O_7$
0%
$Na_2B_4O_7 . 4H_2O$
0%
$Na_2B_4 O_7 . 5 H_2O$
0%
$Na_2B_4 O_7. 10 H_2O$

Explanation

The formulae for mineral borax is :

$Na_2B_4O_7 · 10H_2O$

Mineral Borax is also easily converted to boric acid and other borates, which have many applications.

When mineral borax is added to a flame, it produces a yellow green color. Borax is not used for this purpose in fireworks due to the overwhelming yellow colour of sodium. Boric acid is used to colour methanol flames a transparent green.

Aluminium oxide is not reduced by chemical reactions because:

0%
reducing agent contaminate
0%
the process pollute the environment
0%
aluminium oxide is highly stable
0%
aluminium oxide is reactive

Explanation

$Al_2O_3$ is highly stable it does not get reduced by chemical reaction because the small

$Al^{3+}$ ions and

$O^{2-}$ ions forms a very stable lattice.

No. of water molecules in mohr's salt is :

0%
$7$
0%
$6$
0%
$5$
0%
$8$

Explanation

Ammonium iron(II) sulphate, or Mohr's salt, is the inorganic compound with the formula $(NH_4)_2Fe(SO_4)_2·6H_2O$ . Containing two different cations, $Fe^{2+}$ and $NH_4^{+}$ . It is classified as a double salt of ferrous sulphate and ammonium sulphate.

So Mohr's salt contains 6 water molecules.

Hence option $B$ is correct.

An element of p-block in which last electron enters into s-orbital of valence shell instead of p-orbital is:

0%
$As$
0%
$Ga$
0%
$Te$
0%
$He$

Explanation

Electronic configuration of He is

$1{ s }^{ 2 }$ . It is kept in p-block with group 18 elements even after last electron enters into s-orbital of valence shell instead of p-orbital because it is a noble metal.

In silica

$(SiO_2)$ , each silicon atom is bonded to:

0%
two oxygen atoms
0%
four oxygen atoms
0%
one silicon and two oxygen atoms
0%
one silicon and four oxygen atoms

Explanation

The tetravalency of Si is surrounded by four oxygen atoms. Much of the silicon and oxygen in the Earth’s crust is present as the compound silicon dioxide also known as silica.

Hence, option

$B$ is correct.

The only element of group 13 which does not form a passive layer on the surface while dissolving in con.

$HNO_3$ , but dissolve to form complex is:

0%
boron
0%
aluminium
0%
both
0%
none

Explanation

Boron does not usually react with acids and alkalis but it reacts with acids and alkalis in only highly divided state. When it reacts with

$HN{ O }_{ 3 }$ it gives Boric acid. The reaction occurs at high temperature.

$B+3HN{ O }_{ 3 }\longrightarrow { H }_{ 3 }{ BO }_{ 3 }+3{ NO }_{ 2 }$ which is complex in nature.

Boron forms ionic compounds due to :

0%
higher ionisation enthalpy
0%
lower ionisation enthalpy
0%
small size
0%
both A and C

Explanation

As boron is predominantly a non-metal it hardly loses the electrons and forms ionic bonds. It always forms covalent bonds due to following reasons
1) Small size
2) High nuclear charge
3) High ionisation energy
Hence option

$A,C$ is correct.

Which of the following element of group IIIA element will show allotropy ?

0%
boron
0%
aluminium
0%
gallium
0%
indium

The hot water or steam is decomposed by group 13 elements except:

0%
boron
0%
aluminium
0%
gallium
0%
indium

The halides of group IIIA elements behave as lewis acids. The acceptor ability is maximum for halides of :

0%
$Tl$
0%
$Ga$
0%
$Al$
0%
$B$

Explanation

Option

$(D)$ is correct.

The acceptor ability is maximum for halides of boron due to the availability of 3 valence electrons (

$2s^2 \:2p^1$ ) for covalent bond formation using four orbitals (

$2s, 2p_x, 2p_y$ and

$2p_z$ ) leads to electron deficiency in boron compounds. This deficiency makes them good electron acceptor and thus boron compounds behave as lewis acids.

$Al$ should not be washed with material containing washing soda :

0%
washing soda is expensive
0%
washing soda is easily decomposed
0%
it react with $Al$ to form soluble aluminate.
0%
none of these

Explanation

$2Al+Na_2CO_3+3H_2O \rightarrow 2NaAlO_2+CO_2 +3H_2$

So if $Al$ is washed with washing soda it forms sodium aluminate ( $NaAlO_2$ ) which is soluble in water

Hence option C is correct.

Boron shows single oxidation state due to absence of :

0%
inner pair effect
0%
screening effect
0%
isotope effect
0%
none

Explanation

Boron shows single oxidation state due to absence of inert pair effect.It means that the

$1S^{2}$ electrons in boron participate in chemical bonding(Non participation inner ns electrons in bonding is inert pair effect).
Hence option A is correct.

Bauxite containing impurities of iron oxide is purified by :

0%
Hoop's process
0%
Serpeck's process
0%
Bayer's process
0%
Electrolytic process

Explanation

The Bayer process is the principal industrial method of refining bauxite to produce alumina (aluminium oxide

$Al_2O_3$ ). Bauxite, the most important ore of aluminium, contains only 30–54% aluminium oxide, (alumina).
Hence option C is correct.

The type of hybridization of boron in diborane is :

0%
$sp$
0%
$sp^2$
0%
$sp^3$
0%
$sp^3d^2$

Explanation

The hybridization of

$B_2H_6$ (diborane) is

$sp^{3}$ because each boron molecule has a tetrahedral geometry.
Hence option C is correct

Which of the following has least tendency of catenation?

0%
$C$
0%
$Si$
0%
$Ge$
0%
$Sn$

Explanation

Catenation is the linkage of atoms of the same element into longer chains. Catenation occurs most readily in carbon, which forms covalent bonds with other carbon atoms to form longer chains and structures.

As we move down the group as the size of the atom increases the catenating (linkage of atoms of the same element into longer chains.) ability of an element decreases. So in the given 4th group elements

$Sn$ is having least size. So it has the least tendency of catenation.
Hence option

$D$ is correct.

Which of the following is a metalloid?

0%
$Bi$
0%
$Sn$
0%
$Ge$
0%
$C$

Explanation

Explanation:

Metalloids are elements that have properties intermediate between metals and non-metals.
Metalloids are present in $p-block$ and they lie in between metals and non-metals.
$Ge$ is a metalloid.
$Bi, Sn$ are post-transition metals
$C$ is a non-metal.

Correct Option: $C$
List of Metalloids or Semimetals

Which of the following statement is not correct?

0%
The tendency to exhibit +2 oxidation state for Ge, Sn and Pb is in the order Ge < Sn < Pb
0%
Carbon and silicon mostly exhibit +4 oxidation state in their compounds
0%
Lead in +4 oxidation state acts as an oxidising agent
0%
Tin in +4 oxidation state acts as a good reducing agent

Explanation

The tendency to exhibit

$+2$ oxidation state for Ge, Sn and Pb is in the order

$Ge < Sn < Pb$ due to inert pair effect.Carbon and silicon mostly exhibit

$+4$ oxidation state in their compounds.

Lead in

$+4$ oxidation state acts as an oxidising agent where as tin in

$+2$ act as good reducing agent.

Which of the following is non-metal?

0%
$Ga$
0%
$In$
0%
$Th$
0%
$B$

Explanation

Explanation:

Nonmetals are present in the right corner of the periodic table in $p-block$
Nonmetals accept electrons while metals donate electrons.
$Ga, In$ are a post-transition metal present in $p-block$
$Th$ is a radioactive metal present in the $f-block$ in the actinide series.
$B$ is a nonmetal as it accepts electrons and it is present in $p-block$

Correct Option : $D$

Oxidation of

$Al$ is used in :

0%
preparing foil of $Al$
0%
making utensils
0%
preparing duralumin alloy
0%
thermite welding

Explanation

In thermite welding, aluminium dust is oxidised by the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive. Iron(III) oxide is commonly used:

$Fe_2O_3+2Al\rightarrow Al_2O_3+2Fe$ .

So oxidation of $Al$ takes place in thermite welding

Hence option $D$ is correct.

The hardest substance among the following is:

0%
$Be_2C$
0%
Graphite
0%
Titanium
0%
$SiC$

Explanation

$\begin{array}{l}\text { A) } \mathrm{Be}_{2}\mathrm{C} \text { - Ionic } \\\text { B) Graphite - Molecule or compornd } \\\text { C) Titanium - Metal } \\\text { D) SiC - Ionic }\end{array}$

$\begin{array}{c}\text { hardest - metallic > covalent> Ionic }>\text { molecular }\text { compound }\end{array}$

$\text { Correct answer -C }$

An aqueous solution of borax is :

0%
neutral
0%
acidic
0%
basic
0%
none

Explanation

Hint: If a strong base and weak acid are formed in the reaction then the solution becomes basic in nature.
If a strong acid and weak base are formed in the reaction then the solution becomes acidic in nature.

Explanation:

Reaction of borax with water is shown as below;

$Na_2B_4O_7 + 7H_2O \rightarrow 2NaOH + 4H_3BO_3 + 10H_2O$

In the above reaction, there is the formation of $NaOH$ and $H_3BO_3$ that is boric acid.
Sodium hydroxide is a very strong base. On the other hand, boric acid ( ${H}_{3}{BO}_{3}$ ) is a weak acid.
So, both sodium hydroxide and boric acid try to neutralize each other. But due to the high basic strength of sodium hydroxide, weak acid boric acid cannot completely neutralize it in the solution and the solution will become slightly alkaline in nature.

Correct Option: $C$

In which of the following the inert pair effect is most prominent?

0%
$C$
0%
$Si$
0%
$Ge$
0%
$Pb$

Explanation

In lead (

$Pb$ ) inert pair effect is most prominent because as we move from carbon to lead in the group the tendency of non-participation inner ns electrons in chemical bonding increases due to the large size of atoms.
So Pb is having more tendency of showing inert pair effect.(

$Pb$ is more stable at +2 oxidation state than +4 oxidation state)
Hence option

$D$ is correct.

Element of group

$13$ :

0%
exhibit oxidation state of $+3$ only
0%
form $M^+$ and $M^{+3}$
0%
exhibit oxidation state of $+1$ and $+3$
0%
none of these

Explanation

Element of group

$13$ exhibit oxidation state of

$+1$ and

$+3$ .

$Ga, In$ and

$Tl$ , both

$+1$ and

$+3$ oxidation states are observed. The elements belong to

$13$ group.

For thallium

$+1$ is more stable than

$+3$ due to inert pair effect.

Silicon is used as semiconductor in solid state devices in:

0%
computers
0%
microelectronics
0%
both $A$ and $B$
0%
none of these

Explanation

Option

$(C)$ is correct.

Silicon is used as semiconductor in solid state devices in computers and microelectronics because of its combination of low raw material cost, relatively simple processing, higher band gap and a useful temperature range make it currently the best compromise among the various competing materials. Silicon can be easily oxidized to form thin layer of

$SiO_2$ and thick oxide used else where to isolate components from one another.

Boron can not form more than

$4$ bonds because:

0%
of unavailability of d-orbitals
0%
of unavailabilty of empty p-orbitals
0%
Boron is so smaller
0%
it does not have more valence electrons

CBSE Questions for Class 11 Engineering Chemistry Some P-Block Elements Quiz 7 - MCQExams.com

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Practice Class 11 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Engineering Chemistry Some P-Block Elements Quiz 7 - MCQExams.com

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Practice Class 11 Engineering Chemistry Quiz Questions and Answers

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