CBSE Questions for Class 12 Engineering Chemistry The P-Block Elements Quiz 11 - MCQExams.com

For the manufacture of ammonia by the reaction$$N_{2}+3H_{2} \rightleftharpoons 2NH_{3}+21.9\ K cal$$, the favorable conditions are:
  • low temperature, low pressure & catalyst
  • low temperature, high pressure & catalyst
  • high temperature, low pressure & catalyst
  • low temperature, high pressure 
Among $$BF_{3},N(SiH_{3})_{3},N(CH_{3})_{3}, O(SiH_{3})_{2},CF_{3},CCl_{3}^{-}$$ the number of molecules or molecular ions which have back bonding is:
  • $$1$$
  • $$3$$
  • $$4$$
  • $$all$$
Which of the following does not react with xenon to form compunds?
  • $$OSeF_{5}$$
  • $$OTeF_{5}$$
  • $$F_{2}$$
  • $$N_{2}$$
The catalyst and promoter respectively used in the Haber's process of industrial synthesis of ammonia are:
  • $$Mo,{ V }_{ 2 }{ O }_{ 5 }$$
  • $${ V }_{ 2 }{ O }_{ 5 },Fe$$
  • $$Fe,Mo$$
  • $$Mo,Fe$$
Which of the following elements occur free in nature?
  • Nitrogen
  • Phosphorus
  • Arsenic
  • Antimony
When two atoms of chlorine combine to form one molecule of chlorine gas, the energy of the molecule:
  • Greater than that of separate atom
  • Equal to that of separate atom
  • Lower than that of separate atoms
  • None of the above
Which of the following has $$p\pi -d\pi$$ bonding? 
  • $${ NO }_{ 3 }^{ - }$$
  • $${ CO }_{ 3 }^{ -2 }$$
  • $${ BO }_{ 3 }^{ -3 }$$
  • $${ SO }_{ 3 }^{ -2 }$$
$$p\pi -d\pi \quad$$ bonding is present in:
  • $${ NO }_{ 3 }^{ - }$$
  • $${ SO }_{ 3 }^{ 2- }$$
  • $${ BO }_{ 3 }^{ 3- }$$
  • $${ CO }_{ 3 }^{ 2- }$$
$$NH_3$$ is formed in the following steps
I. $$Ca+2C\rightarrow CaC_2$$    50% yield
II. $$CaC_2+N_2\rightarrow CaCN_2+C$$   100% yield
III. $$CaCN_2+3H_2O\rightarrow 2NH_3+CaCO_3$$        50% yield
To obtain 2 moles $$NH_3$$, calcium required is:
  • 1 mol
  • 2 mol
  • 3 mol
  • 4 mol
Which compound of xenon is not possible ?
  • $$XeF_{2}$$
  • $$XeF_{4}$$
  • $$XeF_{5}$$
  • $$XeF_{6}$$
As per Braun's principle, yield of Ammonia will be more in Haber's process under ______, conditions ($$L=$$ Low; $$H=$$ high; $$T=$$ Temp; $$P=$$ Pressure)
  • $$LT;LP$$
  • $$LT;HP$$
  • $$HT;HP$$
  • $$HT;LP$$
In Carius method, of estimation of halogens, $$250mg$$ of an organic compound gave $$141mg$$ of $$AgBr$$. The percentage of bromine in the compound is:
[Atomic mass $$Ag=108,Br=80$$ amu]
  • $$24$$
  • $$36$$
  • $$8$$
  • $$60$$
The role of zinc stearate in the process of vulcanisation is:
  • to accelerate the process
  • to slow down the process
  • to stop the process
  • to initiate the process
Which of the following characteristics regarding 7 halogens is not correct? 
  • Ionization energy decreases with increase in atomic number.
  • Electronegativity decreases with increase in atomic number.
  • Electron affinity decreases with increase in atomic number.
  • Enthalpy of fusion increases with increase in atomic number
Which of the following alkyl halides is used as a methylating agent?
  • $${C}_{2}{H}_{5}Br$$
  • $${C}_{6}{H}_{5}Cl$$
  • $${CH}_{3}Cl$$
  • $${C}_{2}{H}_{5}Cl$$
An alkyl halide reacts with alcoholic ammonia in a sealed tube, the product formed will be
  • a primary amine
  • a secondary amine
  • a tertiary amine
  • All of the above
Stability of tetrabromides follows the order :
  • $${ SeBr }_{ 4 } < { TeBr }_{ 4 } < { PoBr }_{ 4 }$$
  • $${ SeBr }_{ 4 } < { PoBr }_{ 4 } < { TeBr }_{ 4 }$$
  • $${PoBr }_{ 4 } < { TeBr }_{ 4 } < { SeBr}_{ 4 }$$
  • None of the these
In which reaction ammonia acts as an acid?
  • $${NH}_{3}+HCl\rightarrow {NH}_{4}Cl$$
  • $${NH}_{3}+{H}^{+}\rightarrow {NH}_{4}^{+}$$
  • $${NH}_{3}+Na\rightarrow Na{NH}_{2}+\cfrac{1}{2}{H}_{2}$$
  • $${NH}_{3}$$ cannot act as an acid
One of the following combinations which illustrates the law of reciprocal proportion?
  • N$$_{2}$$O$$_{3}$$,N$$_{2}$$O$$_{4}$$,N$$_{2}$$O$$_{5}$$
  • NaCl ,NaBr ,Nal
  • CS$$_{2}$$ ,CO$$_{2}$$, SO$$_{2}$$
  • MgO,Mg(OH)$$_{2}$$
$$" N < P < As" $$
Above order is incorrect for:
  • Electropositivity
  • Covalent radii
  • Size of $$M^{3-}$$
  • Acidic nature of $$M_2O_3$$ type oxide
The correct order of stability is
  • $${ N }_{ 2 }>{ N }_{ 2 }^{ + }>{ N }_{ 2 }^{ - }$$
  • $${ N }_{ 2 }>{ N }^{ - }_{ 2 }>{ N }_{ 2 }^{ + }$$
  • $${ N }_{ 2 }^{ + }>{ N }^{ - }_{ 2 }>{ N }_{ 2 }$$
  • None of these
A piece of magnesium ribbon was heated to redness in an atmosphere of nitrogen and on cooling water was added the gas evolved was:
  • ammonia
  • hydrogen
  • nitrogen
  • oxygen
An element X forms an oxide $$XO_3$$. What is the valency of X?
  • 1
  • 2
  • 3
  • 6
When a mixture of carbon monoxide and chlorine is exposed to sunlight the product formed is:
  • carbon tetrachloride
  • phosgene
  • phosphine
  • carbon chloride
A mixture of $$NH_4Cl$$ and $$NaCl$$ can be separated by
  • filtration
  • Distillation
  • Sublimation
  • Decantation
In which one of the following processes is iron used as a catalyst in the preparation of ammonia gas?
  • Bayer's process
  • Haber's process
  • Froth floatation process
  • None of the above
Which element forms maximum multiple bonds?
  • N
  • P
  • As
  • Bi
The bond in compound formed from combination of 14 group and 17 group elements of Periodic table will be ..............
  • Electrovalent bond
  • Co-ordinate bond
  • Van der Walls bond
  • Covalent bond
The most favourable condition for the manufacture of $$NH_3$$ is:
  • high temperature and high pressure
  • low temperature and low pressure
  • high temperature and low pressure
  • low temperature and high pressure
In Haber process of  Ammonia production the element used as catalytic promoter to increase the activity of Iron catalyst is .......................
  • NI (Nickel)
  • W (Tungston)
  • V (Vanadium)
  • Mo (Molybednum)
Generally non-metals are non-lustrous. Exception to this property is-
  • Flourine
  • Chlorine
  • Bromine
  • Iodine
Which of the following has more acidic in nature?
  • HClO
  • HClO$$_2$$
  • HClO$$_3$$
  • HClO$$_4$$
An element X combines with hydrogen to form a compound $$XH_3$$. The element X is placed on the right side ofthe periodic table. What is true about the element X?
A. Has 3 valence electrons.
B. Is a metal and is solid.
C. Is a non-metal and is a gas.
D. Has 5 valence electrons.
E. $$XH_3$$  reacts with water to form a basic compound?
  • A, B and C
  • B,C and D
  • C, D and E
  • E, A and B
Which molecule is relatively more stable?
  • $$O_2$$
  • $$H_2$$
  • $$Li_2$$
  • $$N_2$$
Which of the following chalcogen does not make bonds with germanium?
  • Sulfur
  • Selenium
  • Tellurium
  • Polonium
Noble gases have __________ electron affinity.
  • high
  • low
  • zero
  • very low
The wrong statements about $$\displaystyle NH_{3}$$ is :
  • it is oxidised with oxygen at $$\displaystyle 700^{\circ}C$$ in the presence of platinum
  • it gives black precipitate with calomel
  • it can be dried by $$\displaystyle P_{2}O_{5},\ H_{2}SO_{4}\, $$and$$\, CaCl_{2}$$
  • it gives white fumes with HCI
The gas oxygen from thermal decomposition of $$\displaystyle (NH_4)_2 \, Cr_2 O_7 $$ :
  • Oxygen
  • Nitric oxide
  • Ammonia
  • Nitrogen
Thermodynamically most stable allotrope of phosphorus is_____
  • red 
  • white
  • black
  • yellow
Why does one who drinks alcohol get tempted to drink more alcohol?
  • Because $$CO_2$$ increases in liver
  • Because formaldehyde increases in liver
  • Because amount of enzyme P-$$450$$ increases in liver
  • Because amount of disulphiram increases in liver
In Ostwald process of manufacturing of $$HNO_3$$ catalyst used is:
  • Mo
  • Fe
  • Mn
  • Pt
'Kajal' is produced from:
  • stibnite
  • charcoal
  • carbon black
  • asphalt
The halogen $$($$Group $$17$$ elements$$)$$:
  • have an electron configuration of a noble gas less seven electrons
  • are highly electro positive
  • show variable oxidation state of $$-1, +1, +3, +5$$ and $$+7$$ in their various compounds
  • forms a volatile, covalent hydrides $$HX$$ in which the halogen $$(X)$$ shows an oxidation state of $$+1$$
Which noble gas is most soluble in water?
  • $$He$$
  • $$Ar$$
  • $$Ne$$
  • $$Xe$$
Which group of periodic table contains no metal?
  • IA
  • IIIA
  • VIIA
  • VIII
The Group VA element that makes up part of bones and teeth is:
  • N
  • P
  • As
  • Sb
Which one of the following compounds is heated with slaked lime to produce ammonia?
  • $${NH}_{4}Cl$$
  • $$Na{NO}_{3}$$
  • $$K{NO}_{3}$$
  • $$Ca{({NO}_{3})}_{2}$$
Noble gases are absorbed by :
  • Anhydrous calcium chloride
  • Ferric hydroxide
  • Conc. $$H_2SO_4$$
  • Activated coconut charcoal
Why are some elements chemically inert?
  • Because their outermost shell is completely empty
  • Because their outermost shell is completely filled
  • Because their innermost shell is completely empty
  • Because their innermost shell is completely filled
The comparatively high b.pt of $$HF$$ is due to:
  • high reactivity of fluoring
  • small size of hydrogen atom
  • formation of hydrogen bonds and consequent association
  • high IE of flourine
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