JEE Chemistry The P Block Elements MCQs Set C

Question: Ionic radii (in Å) of As³⁺, Sb³⁺ and Bi³⁺ follow the order

• a) Bi³⁺ > Sb³⁺ > As³⁺
• b) Sb³⁺ > Bi³⁺ >As³⁺
• c) As³⁺ > Sb³⁺ > Bi³⁺
• d) None of these

Answer: Bi³⁺ > Sb³⁺ > As³⁺

Question: Which of the following statements is not correct for nitrogen?

• a) d-orbitals are available for bonding
• b) Its electronegativity is very high
• c) It is a typical non-metal
• d) Its molecular size is small

Answer: d-orbitals are available for bonding

Question: Collectively the elements of group 15 are called

• a) pnicogens
• b) nicopen
• c) pnicopens
• d) None of these

Answer: pnicogens

Question: Which one of the following elements is most metallic

• a) Bi
• b) As
• c) P
• d) Sb

Answer: Bi

Question: Which of the follow group 15 element forms metallic bonds in elemental state ?

• a) Bi
• b) P
• c) As
• d) Sb

Answer: Bi

Question: The three important oxidation states of phosphorus are

• a) –3, +3 and +5
• b) –3, +3 and +2
• c) –3, +3 and –5
• d) –3, +3 and +4

Answer: –3, +3 and +5

Question: Nitrogen is relatively inactive element because

• a) dissociation energy of its molecule is fairly high
• b) its electronegativity is fairly high
• c) it has low atomic radius
• d) its atom has a stable electronic configuration

Answer:  dissociation energy of its molecule is fairly high

Question: Pick out the wrong statement.

• a) Catenation tendency is higher in nitrogen when compared with other elements of the same group
• b)  Nitrogen has higher first ionisation enthalpy whencompared with other elements of the same group.
• c) Bismuth forms metallic bonds in elemental state
• d) None of these

Answer: Catenation tendency is higher in nitrogen when compared with other elements of the same group

Question: What causes nitrogen to be chemically inert ?

• a) High bond energy
• b) None of these
• c) Absence of bond polarity
• d) Multiple bond formation in the molecule

Answer: High bond energy

Question: Among the 15th group elements, as we move from nitrogen  to bismuth, the pentavalency becomes less pronounced and trivalency becomes more pronounced due to

• a) Inert pair effect
• b) Large ionization energy
• c) Non metallic character
• d) High electronegativity

Answer: Inert pair effect

Question: Pentavalence in phosphorus is more stable when compared to that of nitrogen even though they belong to same group. This is due to

• a) due to presence of vacant d-orbitals
• b) reactivity of phosphorus
• c) inert nature of nitrogen
• d) dissimilar electronic configuration

Answer: due to presence of vacant d-orbitals

Question: Which one has the lowest boiling point ?

• a) PH₃
• b) SbH₃
• c) NH₃
• d) AsH₃

Answer: PH₃

Question: Most acidic oxide among the following is

• a) N₂O₅
• b) N₂O₄
• c) P₂O₅
• d) As₂O₃

Answer: N₂O₅

Question: Which of the following species has the highest dipole moment

• a) NH₃
• b) PH₃
• c) SbH₃
• d) None of these

Answer: NH₃

Question: Which of the following fluorides does not exist?

• a) NF₅
• b) AsF₅
• c) SbF₅
• d) PF₅

Answer: NF₅

Question: The p-block element of group 15 that forms predominantly basic oxide is

• a) Bi
• b) P
• c) N
• d) As

Answer: Bi

Question: With respect to protonic acids, which of the following statements is correct

• a) PH₃ is less basic than NH₃
• b) PH₃ is more basic than NH₃
• c) PH₃ is equally basic as NH₃
• d) PH₃ is amphoteric while NH₃ is basic

Answer: PH₃ is less basic than NH₃

Question: PCl₅ is possible but NCl₅ does not exist

• a) in N, d-sub-shell is absent
• b) ionization energy of N is very high
• c) it does not like Cl
• d) None of these

Answer: in N, d-sub-shell is absent

Question: Maximum covalency of nitrogen is

• a) 4
• b) 3
• c) 5
• d) 6

Answer: 4

Question: Elements of group-15 form compounds in +5 oxidation state. However, bismuth forms only one well characterised compound in +5 oxidation state. The compound is

• a) BiF₅
• b) Bi₂S₅
• c) BiCl₅
• d) None of these

Answer: BiF₅

Question: Pure nitrogen is prepared in the laboratory by heating a mixture of

• a) NH₄Cl + NaNO₂
• b) NH₄NO₃ + NaCl
• c) NH₄OH + NaCl
• d) NH₄Cl + NaOH

Answer:  NH₄Cl + NaNO₂

Question: On heating ammonium dichromate and barium azide separately we get

• a) N₂ in both cases
• b) N₂ with ammonium dichromate and NO with barium azide
• c) N₂O with ammonium dichromate and N₂ with barium azide
• d) None of these

Answer: N₂ in both cases

Question: In Haber’s process for the manufacture of NH₃

• a) finely divided nickel is used as a catalyst
• b) finely divided iron is used as a catalyst
• c) finely divided molybdenum is used as a catalyst
• d) no catalyst is necessary

Answer: finely divided nickel is used as a catalyst

Question: Ammonia on reaction with hypochlorite anion can form

• a) Both
• b) N₂H₄
• c) NH₄Cl
• d) None of these

Answer: Both

Question: NH₃ gas is dried over

• a) CaO
• b) HNO₃
• c) CuSO₄
• d) P₂O₅

Answer: CaO

Question: The shape of ammonia molecule is

• a) pyramidal
• b) octahedral
• c) tetrahedral
• d) planar triangle

Answer: pyramidal

Question: One mole of calcium phosphide on reaction with excess water gives

• a) two moles of phosphine
• b) one mole of phosphorus pentoxide
• c) two moles of phosphoric acid
• d) one mole of phosphine

Answer: two moles of phosphine

Question: PH₃, the hydride of phosphorus is

• a) covalent
• b) ionic
• c) metallic
• d) non-metallic

Answer: covalent

Question: Phosphine is not obtained by which of the following reaction

• a) Red P is heated with NaOH
• b) White P is heated with NaOH
• c) Phosphorus trioxide is boiled with water
• d) Ca₃P₂ reacts with water

Answer: Red P is heated with NaOH

Question: Phosphine is not evolved when

• a) metaphosphoric acid is heated
• b) calcium hypophosphite is heated
• c) phosphorus acid is heated
• d) white phosphorus is boiled with a strong solution of Ba(OH)₂

Answer: metaphosphoric acid is heated

Question: Pure phosphine is not combustible while impure phosphine is combustible, this combustibility is due to presence of

• a) P₂H₄
• b) N₂
• c) PH₅
• d) P₂O₅

Answer: P₂H₄

Question: When orthophosphoric acid is heated to 600°C, the product formed is

• a) HPO₃
• b) P₂O₅
• c) PH₃

Answer: HPO₃

Question: P₂O₅ is heated with water to give

• a) orthophosphoric acid
• b) phosphorous acid
• c) hypophosphoric acid
• d) hypophosphorous acid

Answer: orthophosphoric acid

Question: Basicity of orthophosphoric acid is

• a) 3
• b) 5
• c) 2
• d) 4

Answer: 3

Question: PCl₃ reacts with water to form

• a) H₃PO₄ and HCl
• b) H₃PO₄
• c) PH₃
• d) POCl₃

Answer: H₃PO₄ and HCl

Question: H₃PO₂ is the molecular formula of an acid of phosphorus. Its name and basicity respectively are

• a) hypophosphorous acid and one
• b) hypophosphoric acid and two
• c) hypophosphorous acid and two
• d) phosphorus acid and two

Answer: hypophosphorous acid and one

Question: Number of sigma bonds in P₄O₁₀ is

• a) 16
• b) 7
• c) 6
• d) 17

Answer: 16

Question: The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorous acid is

• a) two
• b) three
• c) one
• d) zero

Answer: two

Question: The number of P – O – P bonds in cyclic metaphosphoric acid is

• a) three
• b) zero
• c) two
• d) four

Answer: three

Question: Oxidation states of P in H₄P₂O₅ , H₄P₂O₆ , and H₄P₂O₇ , are respectively:

• a) + 3, + 4, + 5
• b) + 5, + 3, + 4
• c) + 3, + 5, + 4
• d) + 5, + 4, + 3

Answer:  + 3, + 4, + 5

Question: How many bridging oxygen atoms are present in P₄O₁₀?

• a) 6
• b) 2
• c) 5
• d) 4

Answer: 6

Question: Which of the following statements is not valid for oxoacids of phosphorus?

• a) Hypophosphorous acid is a diprotic acid
• b) Orthophosphoric acid is used in the manufacture of triple superphosphate
• c) All oxoacids contain tetrahedral four coordinated phosphorus
• d) All oxoacids contain atleast one P = O and one P — OH group

Answer: Hypophosphorous acid is a diprotic acid

Question: What is hybridization of P in PCl₅ ?

• a) sp³d
• b) sp³
• c) sp²
• d) None of these

Answer: sp³d

Question: Which of the following is a cyclic phosphate ?

• a) H₅P₅O₁₅
• b) H₃P₃O₁₀
• c) H₆P₄O₁₃
• d) None of these

Answer: H₅P₅O₁₅

Question: Orthophosphoric acid is

• a) tribasic
• b) monobasic
• c) dibasic
• d) tetrabasic

Answer: tribasic

Question: The oxyacid of phosphorous in which phosphorous has the lowest oxidation state is

• a) hypophosphorous acid
• b) orthophosphoric acid
• c) pyrophosphoric acid
• d) None of these

Answer: hypophosphorous acid

Question: The number of P—O—P bonds in cyclic metaphosphoric acid is

• a) three
• b) zero
• c) two
• d) four

Answer: three

Question: Among the oxyacids of phosphorus, the dibasic acid is

• a) H₃PO₃
• b) HPO₃
• c) H₃PO₂
• d) None of these

Answer: H₃PO₃

Question: The basicity of pyrophosphorus acid is

• a) 2
• b) 1
• c) 4
• d) 5

Answer: 2

Question: The oxidation state of phosphorus in cyclotrimetaphosphoric acid is

• a) +5
• b) +2
• c) +3
• d) –3

Answer: +5

Question: Which acid has P – P linkage

• a) Hypophosphoric acid
• b) Metaphosphoric acid
• c) Pyrophosphoric acid
• d) Orthophosphoric acid

Answer: Hypophosphoric acid

Question: In a cyclotrimetaphosphoric acid molecule, how many single and double bonds are present?

• a) 3 double bonds; 9 single bonds
• b) 6 double bonds; 6 single bonds
• c) 3 double bonds; 12 single bonds
• d) Zero double bonds; 12 single bonds

Answer: 3 double bonds; 9 single bonds

Question: Strong reducing behaviour of H₃PO₂ is due to

• a) Presence of one –OH group and two P–H bonds
• b) High electron gain enthalpy of phosphorus
• c) Presence of two –OH groups and one P–H bond
• d) Low oxidation state of phosphorus

Answer: Presence of one –OH group and two P–H bonds

Question: Electron affinity of sulphur is

• a) more than O and Se
• b) more than O but less than Se
• c) less than O but more than Se
• d) equal to O and Se

Answer: more than O and Se

Question: All the elements of oxygen family are

• a) polymorphic
• b) metalloids
• c) non metals
• d) radioactive

Answer: polymorphic

Question: Which shows maximum catenation property ?

• a) S
• b) Te
• c) Se
• d) O

Answer: S

Question: Oxygen and sulphur both are the members of the same group in periodic table but H₂O is liquid while H₂S is gas because

• a) water molecules are having weak hydrogen bonds between them
• b) H₂S is weak acid
• c) electronegativity of sulphur is more
• d) molecular weight of water is more

Answer: water molecules are having weak hydrogen bonds between them

Question: Which of the following hydrides has the lowest boiling point

• a) H₂S
• b) H₂Te
• c) H₂O
• d) None of these

Answer: H₂S

Question: Which of the following hydrides is most acidic ?

• a) H₂Te
• b) H₂O
• c) H₂S
• d) H₂Se

Answer: H₂Te

Question: Which of the following hydrides shows the highest boiling point ?

• a) H₂O
• b) H₂S
• c) H₂Se
• d) None of these

Answer: H₂O

Question: Which is the best oxidising agent among the following ?

• a) O
• b) Te
• c) S
• d) Se

Answer: O

Question: Which of the following oxide is amphoteric

• a) SnO₂
• b) CaO
• c) CO₂
• d) SiO₂

Answer: SnO₂

Question: Which of the following is not correctly matched

• a) SF₆ – solid
• b) SeF₄ – liquid
• c) SF₄ – gas
• d) None of these

Answer: SF₆ – solid

Question: The compound which gives off oxygen on moderate heating is

• a) mercuric oxide
• b) aluminium oxide
• c) cupric oxide
• d) zinc oxide

Answer: mercuric oxide

Question: Oxygen molecule is

• a) paramagnetic with two unpaired electrons
• b) paramagnetic with no unpaired electron(s)
• c) diamagnetic with two unpaired electrons
• d) diamagnetic with no-unpaired electron(s)

Answer: paramagnetic with two unpaired electrons

Question: The number of electrons that are paired in oxygen molecule are

• a) 14
• b) 16
• c) 12
• d) 7

Answer: 14

Question:  On heating KClO₃ we get

• a) KCl + O₂
• b) KCl + O₂ + O₃
• c) KCl + O₃
• d) None of these

Answer: KCl + O₂

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) It is beneficial to us as it stops U.V radiation
• b) It is harmful as it stops useful radiation
• c) Ozone has a triatomic linear molecule
• d) Conversion of O₃ to O₂ is an endothermic reaction

Answer: It is beneficial to us as it stops U.V radiation

Question: Oxygen gas can be prepared from solid KMnO₄ by

• a) strongly heating the solid
• b) treating the solid with H₂ gas
• c) dissolving the solid in dil. H²SO₄
• d) dissolving solid in dil. HCl

Answer: strongly heating the solid

Question: Which of the following statements is correct

• a) Ozone is an allotropic modification of oxygen
• b) Ozone has no relationship with oxygen
• c) Ozone is an isomer of oxygen
• d) Ozone is a resonance hybrid of oxygen

Answer: Ozone is an allotropic modification of oxygen

Question: Which of the following on thermal decomposition gives oxygen gas ?

• a) All of these
• b) Pb₃O₄
• c) Ag₂O
• d) PbO₂

Answer: All of these

Question: Which of the following is an acidic oxide?

• a) Mn₂O₇
• b) N₂O
• c) BaO
• d) Na₂O

Answer: Mn₂O₇

Question: Atomicity of sulphur in rhombic sulphur is

• a) 8
• b) 1
• c) 2
• d) 6

Answer: 8

Question: Which of the following is not oxidized by O₃ ?

• a) KMnO₄
• b) KI
• c) FeSO₄
• d) None of these

Answer: KMnO₄

Question: Which of the following form of the sulphur shows paramagnetic behaviour

• a) S₂
• b) S₈
• c) S₆
• d) All of these

Answer: S₂

Question: Which of the following oxo acid of sulphur has O–O bond

• a) H₂S₂O₈
• b) H₂S₂O₅
• c) H₂S₂O₇
• d) None of these

Answer: H₂S₂O₈

Question: Carbohydrates on reaction with conc. H₂SO₄ becomes charred due to

• a) dehydration
• b) oxidation
• c) hydrolysis
• d) hydration

Answer: dehydration

Question: Which of the following is the key step in the manufacture of sulphuric acid ?

• a) Conversion of SO₂ to SO₃ by the reaction with oxygen in presence of catalyst
• b) Burning of sulphur or sulphide ores in air to generate SO₂
• c) Absorption of SO₃ in H₂SO₄ to give oleum
• d) None of these

Answer: Conversion of SO₂ to SO₃ by the reaction with oxygen in presence of catalyst

Question: Hybridization of S in SO₃ is

• a) sp²
• b) sp³
• c) sp²d
• d) None of these

Answer: sp²

Question: By which of the following SO₂ is formed

• a) Reaction of conc. H₂SO₄ with Cu
• b) None of these
• c) Hydrolysis of dil. H₂SO₄
• d) Reaction of dil. H₂SO₄ with O₂

Answer: Reaction of conc. H₂SO₄ with Cu

Question: Bleaching action of SO₂ is due to its

• a) reducing property
• b) oxidising property
• c) acidic property
• d) basic property

Answer: reducing property