MCQ Questions Chapter 7 The p – Block Elements Class 12 Chemistry

Please refer to MCQ Questions Chapter 7 The p – Block Elements Class 12 Chemistry with answers provided below. These multiple-choice questions have been developed based on the latest NCERT book for class 12 Chemistry issued for the current academic year. We have provided MCQ Questions for Class 12 Chemistry for all chapters on our website. Students should learn the objective based questions for Chapter 7 The p – Block Elements in Class 12 Chemistry provided below to get more marks in exams.

Chapter 7 The p – Block Elements MCQ Questions

Please refer to the following Chapter 7 The p – Block Elements MCQ Questions Class 12 Chemistry with solutions for all important topics in the chapter.

Question. Which gas is evolved by the treatment of magnesium with very dilute solution of HNO₃? 
(a) N₂
(b) NO₂
(c) H₂
(d) H₂O

Question. Which of the following is not correct? 
(a) Ammonia is used as refrigerant
(b) A mixture of Ca(CN)₂ and C is known as nitrolirn
(c) A mixture of Ca(H₂PO₄ )₂ and CaSO₄ . 2H₂O is known as superphosphate of lime
(d) Hydrolysis of NCl₃ gives NH₃ and HOCl

Question. Dinitrogen pentoxide (N₂O₅ ), a colourless solid, is prepared by 
(a) heating NH₄NO₂ with an excess of oxygen
(b) dehydrating HNO₃ with Cao
(c) dehydrating HNO₃ with P₄O₁₀
(d) heating a mixture of HNO₂ and Ca(NO₃)₂

Question. Among the following observations, the correct one that differentiates between SO₃^2- and SO₄^2- is 
(a) both form precipitate with BaCl₂ , SO₃^2- dissolves in HCl but SO₄^2- does not
(b) SO₃^2- forms precipitate with BaCl₂ , SO₄^2- does not
(c) SO₄^2- forms precipitate with BaCl₂, SO₃^2- does not
(d) both form precipitate with BaCl₂, SO₄^2- dissolves in HCl but SO₃^2- does not

Question. PCl₃ and cold water reacts to produce which of the following ? 
(a) H₃PO₃
(b) H₃PO₂
(c) H₄P₂O₇
(d) H₃PO₄

Question. Which of the following is kept in water ?
(a) White phosphorus
(b) Sodium
(c) Potassium
(d) Calcium

Question. White phosphorus is
(a) a monoatomic gas
(b) P₄, a tetrahedral solid
(c) P₈, a crown
(d) a linear diatomic molecule

Question. Consider the following statements.
I. NCl₅ does not exist while PCl₅ does.
II. Both O₂⁺ and NO are paramagnetic.
III. The three C—O bonds are not equal in carbonate ion.
IV. Lead prefers to form tetravalent compound.
Which of the above statements are incorrect ?
(a) I and m
(b) I, III and IV 
(c) II an III
(d) III and IV

Question. Which phosphorus reacts with KOH solution to produce phosphine gas ? 
(a) White phosphorus
(b) Red phosphorus
(c) Both (a) and (b)
(d) None of the above

Question. Incorrect statement for pyrophosphoric acid H₄P₂O₅ is
(a) it contains P in + 5 oxidation state 
(b) it is dibasic acid
(c) it is strongly reducing in nature
(d) it contains one P—O—P bond

Question. A crystalline solid X reacts with dil. HCl to liberate a gas Y. Y decolourises acidified KMnO₄ . When a gas Z is slowly passed into an aqueous solution of Y, colloidal sulphur is obtained X and Z could be respectively
(a) Na₂S ,SO₃
(b) Na₂SO₄ ,H₂S
(c) Na₂SO₃ ,H₂S
(d) Na₂SO₄ ,SO₂

Question. Conversion of oxygen into ozone is non-spontaneous at
(a) all temperature
(b) high temperature 
(c) room temperature
(d) low temperature

Question. Which of the following oxide does not form acidic aqueous solution ? 
(a) N₂O₃
(b) NO₂
(c) N₂O₅
(d) NO

Question. Which blue-liquid is obtained on reacting amounts of two gases at – 30° C?
(a) N₂O
(b) N₂O₃
(c) N₂O₄
(d) N₂O₅

Question. When heated NH₃ is passed over CuO, gas evolved is
(a) N₂
(b) N₂O
(c) HNO₃
(d) NO₂

Question. When the substances CCI₄, CH₄ and CF₄ are arranged in order of increasing boiling point, what is the correct order ? 
(a) CCI₄, CF₄, CH₄
(b) CH₄, CF₄, CCI₄
(c) CF₄, CCI₄, CH₄
(d) CF₄, CH₄, CCI₄

Question. (SiH₃ )₃ N is
(a) planar
(c) octahedral
(b) pyramidal
(d) tetrahedral

Question. The metal which does not form ammonium nitrate by reaction with dilute nitric acid is 
(a) Al
(b) Fe
(c) Pb
(d) Mg

Question. The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorus acid is 
(a) three
(b) one
(c) two
(d) zero

Question. Which requires catalyst ?
(a) S + O₂ → SO₂
(b) 2SO₂ + O₂ → 2SO₃
(c) C + O₂ → CO₂
(d) All of the above

Question. Which of the following is tetrabasic acid? 
(a) Orthophosphorus acid
(b) Orthophosphric acid
(c) Meta phosphoric acid
(d) Pyrophosphoric acid

Question. When plants and animals decay, the organic nitrogen is converted into inorganic nitrogen. The inorganic nitrogen is in the form of 
(a) ammonia
(b) elements ofnitrogen
(c) nitrates
(d) nitrides

Question. The correct statements (s) about O₃ is (are)
(a) O—Obond lengths are equal
(b) thermal decomposition of O₃ is endothermic
(c) O₃ is diamagnetic in nature
(d) O₃ has a bent structure

Question. In which of these processes platinum is used as a catalyst?
(a) Oxidation of ammonia to form HNO₃
(b) Hardening of oils
(c) Production of synthetic rubber
(d) Synthesis of methanol

Question. In the manufacture of s ulphuric acid by contact process, Tyndall box is used to 
(a) filter dust particles
(b) remove impurities
(c) convert SO₂ to SO₃
(d) test the presence of dust particles

Question. The structure of 01thophosphoric acid is 

Question. Which of the following is a tribasic acid ?
(a) H₃PO₄
(b) HPO₃
(c) H₄P₂O₇
(d) H₄P₂O₆

Question. Iron is dropped in dil. HNO₃, it gives
(a) ferric nitrate
(b) ferric nitrate and NO₂
(c) ferrous nitrate and ammonium nitrate
(d) ferrous nitrate and nitric oxide

Question. Which one of the following pairs of reactants does not form oxygen when they react with each other ? 
(a) F₂, NaOH solution (hot, cone.)
(b) F₂, H₂O
(c) Cl₂ , NaOH solution (cold, clilute)
(d) CaOCl₂ , H₂SO₄ (dilute, small amount)

Question. In Ostwald process of manufacturing of HNO₃ , catalyst used is 
(a) Mo
(b) Fe
(c) Mn
(d) Pt

Question. Which is most thermodynamically stable allotropic form of phosphorus ?
(a) Red
(b) White
(c) Black
(d) Yell ow

Question. The atomicity of sulphur in rhombic sulphur is 
(a) 1
(b) 2
(c) 4
(d) 6
(e) 8

Question. When H₂S gas is passed through nitric acid, the product is
(a) rhombic S 
(b) prismatic S ( colloidal)
(c) amorphous S
(d) monoclinic S
(e) plastic S

Question. The substance which does not liberate oxygen on treatment with ozone is 
(a) PbS
(b) HCl
(c) SO₂
(d) Hg

Question. Which of the following statements regarding sulphur is incorrect ?
(a) SO₂ molecule is paramagnetic
(b) The vapour at 200°C consists mostly of S₈ rings
(c) At 600°C the gas main] y consists of S₂ molecules
(d) The oxidation state of sulphur is never less than+ 4 in its compounds

Question. Which one of the following is not true at room temperature and pressure?
(a) P₄O₁₀ is a white solid
(b) SO₂ is a colourless gas
(c) SO₃is a colourless gas
(d) NO₂ is brown gas

Question. The correct order ofreducing abilities of hydrides of V group elements is 
(a) NH₃ < PH₃ < AsH₃ < SbH₃ < BiH₃
(b) NH₃ > PH₃ > AsH₃ > SbH₃ > BiH₃
(c) NH₃ < PH₃ > AsH₃ > SbH₃ > BiH₃
(d) SbH₃ > BiH₃ > AsH₃ > NH₃ > PH₃

Question. Oleum is chemically
(a) H₂SO₃
(b) H₂SO₅
(c) H₂S₂O₇
(d) H₂S₂O₈

Question. Concentrated sulphuric acid can be reduced by
(a) NaCl
(b) NaF 
(c) NaOH
(d) NaNO₃
(e) NaBr

Question. Reaction of PCl₃ and PhMgBr would give
(a) bromobenzene
(b) chlorobenzene
(c) triphenylphosphine
(d) dichlorobenzene

Question. Which compound does not has S—S bond ?
(a) Na₂S₂O₄
(b) Na₂S₄O₆
(c) Na₂S₂O₃
(d) Na₂S₂O₇

Question. The function of Fe(OH)₃ in the contact process is
(a) to remove arsenic impurity
(b) to detect colloidal impurity
(c) to remove moisture
(d) to remove dust particles

Question. The ore that is concentrated by the froth floatation process is
(a) cryolite
(b) cuprite
(c) calamine
(d) chalcopyrites

Question. A gas, that relights glowing splinter, is
(a) H₂  
(b) O₂
(c) N₂
(d) NO₂

Question. Which element is not considered as ‘chalcogens’?
(a) Selenium
(b) Oxygen 
(c) Sulphur
(d) Polonium

Question. Which of the following salt would give SO₂ with hot and dil. H₂SO₄ and also decolourises Br₂ water? 
(a) Na₂SO₃
(b) NaHSO₄
(c) Na₂SO₄
(d) Na₂S

Question. Excess of PCl₅ reacts with cone. H₂SO₄ giving 
(a) chlorosulphonic acid
(b) thionyl chloride
(c) sulphuryl chloride
(d) sulphurous acid

Question. In presence of moisture, SO₂ can 
(a) act as oxidant
(b) act as reductant
(c) gain electron
(d) not act as reductant

Question. Ozone is used for purifying water because 
(a) it dissociates and release oxygen
(b) do not leave any foul smell like chlorine
(c) kills bacteria, cyst, fungi and acts as a biocide
(d) All of the above

Question. Oxalic acid when heated with cone. H₂SO₄ , gives
(a) H₂O₂ and CO₂
(b) CO and CO₂
(c) H₂O₂ and CO
(d) CO₂ and H₂S

Question. Copper turnings on heating with cone. H₂SO₄ produce
(a) H₂S
(b) O₂
(c) SO₃
(d) SO₂

Question. Sulphur does not exist as S₂ molecule because 
(a) it is less electronegative
(b) it is not able to constitute pπ-pπ bonds
(c) it has ability to exhibit catenation
(d) of tendency to show variable oxidation states

Question. H₂ Sis not a/an
(a) reducing agent
(b) acidic
(c) oxidising agent
(d) None of these

Question. In the laboratory H₂S gas is prepared by using black lumps and dil. H₂SO₄ . The black lumps are 
(a) FeSO4
(b) MnO₂
(c) FeS
(d) FeSO₃

Question. Polyanion formation is maximum in 
(a) nitrogen
(b) sulphur
(c) oxygen
(d) boron

Question. When cone. H₂SO₄ is heated with P₂O₅ , the acid is converted into 
(a) sulphur trioxide
(b) sulphur dioxide
(c) sulphur
(d) a mixture of sulphur dioxide and sulphur trioxide

Question. Which among the following statements are correct ?
I. Carbon monoxide is neutral whereas SO₃ is acidic.
II. Potassium oxide is basic whereas nitrous oxide is acidic.
III. Aluminium and zinc oxides are amphoteric.
IV. Sulphur trioxide is aciclic whereas phosphorus pentaoxide is basic.
V. Carbon dioxide is neutral whereas sulphur d ioxide is amphoteric. 
(a) II and III
(b) I and IV
(c) I and III
(d) II and IV
(e) III and V

Question. Select the incon-ect statement among the following.
(a) O₃ is used as germicide for purification of air
(b) In O₃ , O—O bond length is identical with that of molecular oxygen.
(c) O₃ molecule is angular in shape.
(d) O₃ is an oxidising agent.

Question. Olewn is 
(a) castor oil
(b) oil of vitriol
(c) fuming H₂SO₄
(d) None of these

Question. Which of the following is not correct? 
            _{Silent electric}
(a) 30₂     ⇔       2O₃ ; ΔH = – 284.5 kJ
             ^discharge
(b) Ozone undergoes addition reaction with unsaturated carbon compounds
(c) Sodium thiosulphate reacts with I₂ to form sodium tetratbionate and sodium iodide
(d) Ozone oxidises lead sulphide to lead sulphate

Question. At T (K.), 100 L of dry oxygen is present in a sealed container. It is subjected to silent electric discharge, till the volumes of oxygen and ozone become equal. What is the volume (in litres) of ozone formed at T (K)? 
(a) 50
(b) 60
(c) 30
(d) 40

Question. Which of the following is most acidic hydride ofnitrogen?
(a) N₃H
(b) NH₃ 
(c) N₂H₄
(d) Both N₃H and NH₃

Question. Which is tribasic acid ?
(a) H₃PO₂
(b) H₃PO₄
(c) H₄P₂O₇
(d) H₃PO₃

Question. Which of the following statement is true?
(a) H₃PO₃ is a stronger acid than H₂SO₃
(b) In aqueous medium HF is a stronger acid than HCl
(c) HCIO₄ is a weaker acid than HCIO₃
(d) HNO₃ is a stronger acid than HNO₂

Question. Which of the following is the correct order of increasing enthalpy of vaporisation ? 
(a) NH₃ < PH₃ < AsH₃
(b) AsH₃ < PH₃ < NH₃
(c) PH₃ < AsH₃ < NH₃
(d) NH₃ < AsH₃ < PH₃

Question. Which of the following is not oxiclised by O₃? 
(a) KI
(b) FeSO₄
(c) KMnO₄
(d) K₂MnO₄

Question. Which one is con-ect statement ? 
(a) Basicity of H₃PO₄ and H₃PO₃ is 3 and 3 respectively
(b) Acidity of H₃PO₄ and H₃PO₃ is 3 and3 respectively
(c) Acidity of H₃PO₄ and H₃PO₃ is 3 and2 respectively
(d) Basicity of H₃PO₄ and H₃PO₃ is 3 and 2 respectively

Question. The con-ect order of boiling points of the hydrides of nitrogen family is 
(a) NH₃ > PH₃ > AsH₃ > SbH₃
(b) PH₃ < AsH₃ < NH₃ < SbH₃
(c) NH₃ < PH₃ < SbH₃ < AsH₃
(d) NH₃ < PH₃ < AsH₃ < SbH₃

Question. SO₂ + H₂S → Product.The final product is 
(a) H₂O + S
(b) H₂SO₄
(c) H₂SO₃
(d) H₂SO₃

Question. The stable bivalency ofpb and trivalency of Bi is
(a) due to d contraction in Pb and Bi
(b) due to relativistic contraction of the fu.orbitals of Pb and Bi, leading to inert pair effect
(c) due to screening effect
(d) due to attainment of noble liquid configuration

Question. Atomicity of sulphur in rhombic sulphur is
(a) 1
(b) 2
(c) 8
(d) 6

Question. Oxygen molecule is
(a) diamagnetic with no-unpaired electron(s)
(b) diamagnetic with two unpaired electrons
(c) paramagnetic with two unpaired electrons
(d) paramagnetic with no unpaired electron(s)

Question. Which of the following on thermal decomposition gives oxygen gas ?
(a) Ag₂O
(b) Pb₃O₄
(c) PbO₂
(d) All of these

Question. On heating KClO₃ we get
(a) KClO₂ + O₂
(b) KCl + O₂
(c) KCl + O₃
(d) KCl + O₂ + O₃

Question. Which of the following is not oxidized by O₃ ?
(a) KI
(b) FeSO₄
(c) KMnO₄
(d) K2MnO₄

Question. About 20 km above the earth, there is an ozone layer. Which one of the following statements about ozone and ozone layer is true?
(a) Ozone has a triatomic linear molecule
(b) It is harmful as it stops useful radiation
(c) It is beneficial to us as it stops U.V radiation
(d) Conversion of O₃ to O₂ is an endothermic reaction

Question. Oxygen gas can be prepared from solid KMnO₄ by :
(a) treating the solid with H₂ gas
(b) strongly heating the solid
(c) dissolving the solid in dil. H₂SO₄
(d) dissolving solid in dil. HCl

Question. Which of the following statements is correct :
(a) Ozone is a resonance hybrid of oxygen
(b) Ozone is an isomer of oxygen
(c) Ozone has no relationship with oxygen
(d) Ozone is an allotropic modification of oxygen

Question. Which of the following is an acidic oxide?
(a) Mn₂O₇
(b) Na₂O
(a) N₂O
(b) BaO

Question. The compound which gives off oxygen on moderate heating is :
(a) cupric oxide
(b) mercuric oxide
(c) zinc oxide
(d) aluminium oxide

Question. Which of the following form of the sulphur shows paramagnetic behaviour ?
(a) S₈
(b) S₆
(c) S₂
(d) All of these

Question. Number of bonds in SO₂ are
(a) two σ and two π
(b) two σ and one π
(c) two σ and three π
(d) None of these 

Question. What is X in the following reaction ?

(a) V₂O₅
(b) CuO
(c) CuCl₂
(d) MnO₂

Question. Which of the following oxo acid of sulphur has O–O bond ?
(a) H₂S₂O₇
(b) H₂S₂O₈
(c) H₂S₂O₆
(d) H₂S₂O₅

Question. The number of electrons that are paired in oxygen molecule are
(a) 16
(b) 12
(c) 14
(d) 7

Question. Bleaching action of SO₂ is due to its
(a) oxidising property
(b) acidic property
(c) reducing property
(d) basic property

Question. Hybridization of S in SO₃ is
(a) sp²
(b) sp³
(c) sp²d
(d) sp³d²

Question. Carbohydrates on reaction with conc. H₂SO₄ becomes charred due to
(a) hydrolysis
(b) dehydration
(c) hydration
(d) oxidation

Question. By which of the following SO₂ is formed ?
(a) Reaction of dil. H₂SO₄ with O₂
(b) Hydrolysis of dil. H₂SO₄
(c) Reaction of conc. H₂SO₄ with Cu
(d) None of these

Question. Which of the following is the key step in the manufacture of sulphuric acid ?
(a) Burning of sulphur or sulphide ores in air to generate SO₂
(b) Conversion of SO₂ to SO₃ by the reaction with oxygen in presence of catalyst.
(c) Absorption of SO₃ in H₂SO₄ to give oleum.
(d) Both (b) and (c)

Question. Calcium cyanamide on treatment with steam produces
(a) NH₃ + CaO
(b) NH₃ + CaHCO₃
(c) NH₃+ CaCO₃
(d) NH₃ + Ca(OH)₂

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