CBSE Class 12 Chemistry The p Block Elements MCQs

Question : The ion or group detected by K₂[HgI₄] is

Answer : D

Question : Which gas cannot be collected over water ?

(a) O₂ 
(b) PH₃
(c) N₂
(d) SO₂

Answer : D

Question : The correct order of in creasing oxidising power is :

Answer : D

Question : H₂S does not produce metallic sulphide with :

(a) CuCl₂
(b) COCl₂
(c) CdCl₂
(d) ZnCl₂

Answer : B

Question : The correct order of acid strength of oxyacids is: 

Answer : C

Question :  Chlorine acts as a bleaching agent only in presence of:presence of

(a) Sunlight
(b) Moisture
(c) Dry air   
(d) Pure oxygen

Answer : B

Question :  The laughing gas is:

(a) NO    
(b) N₂O
(c) N₂O4
(d) N₂O5

Answer : B

Question :  The correct decreasing order of basic strength is: 

Answer : C

Question : Iodide of Millon's base is

(a) HIO₃             
(b) K₂HgI₄
(c) NH₂HgO.HgI 
(d) Hg(NH₂ )I

Answer : C

Question : Which of the following is not the characteristic of interhalogen compounds?

(a) they are covalent
(b) more reactive than halogens
(c) have low B.P. and high volatile
(d) quite unstable but not explosive

Answer : C

Question : The tribasic acid is :

(a) H₃PO₄
(b) H₃PO₃
(c) H₃PO₂
(d) HPO₃

Answer : A 

Question : The strongest oxidising agent is

(a) F₂ 
(b) Cl₂
(c) I₂  
(d) Br₂

Answer : A 

Question : The correct order of solubility in water for He, Ne, Ar, Kr, Xe is

(a) He > Ne > Ar > Kr > Xe
(b) Xe > Kr > Ar > Ne > He
(c) Ne > Ar > Kr > He > Xe
(d) Ar > Ne > He > Kr > Xe

Answer : B 

Question : Which of the following compound is a tribasic acid?

(a) H₃PO₂
(b) H₃PO₄
(c) H₃PO₃
(d) H₄P₂O₇

Answer : B

Question : The mixture of concentrated HCl and HNO₃ made in 3 : 1 ratio contains

(a) ClO₂
(b) NOCl
(c) NCl₃
(d) N₂O₄

Answer : B 

Question : The element which forms oxides in all oxidation states varying from +1 to +5 is

(a) N  
(b) P
(c) As 
(d) Sb

Answer : A 

Question : The statement true for N₃^– is

(a) it has non-linear structure
(b) it is called pseudohalogen
(c) the formal oxidation state of nitrogen in this anion is – 1
(d) it is isoelectronic with NO₂

Answer : D 

Question : For electron affinity of halogens which of the following is correct?

(a) Br > F
(b) F > Cl
(c) Br > Cl
(d) F > I

Answer : D 

Question : The number of P–O–P bridges in the structure of phosphorus pentoxide and phosphorus trioxide are respectively

(a) 6, 6
(b) 5, 5
(c) 5, 6
(d) 6, 5

Answer : A 

Question : Tincture of iodine is

(a) Aqueous solution of I₂
(b) Solution of I₂ in aqueous KI
(c) Alcoholic solution of I₂
(d) Aqueous solution of KI

Answer : C 

Question : Which two of the following salts are used for preparing iodized salt?
(i) KIO₃ (ii) KI
(iii) I₂    (iv) HI

(a) (i) and (ii)  
(b) (i) and (iii)
(c) (ii) and (iv) 
(d) (iii) and (iv)

Answer : A 

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

(a) As³⁺ > Sb³⁺ > Bi³⁺
(b) Sb³⁺ > Bi³⁺ >As³⁺
(c) Bi³⁺ > As³⁺ > Sb³⁺
(d) Bi³⁺ > Sb³⁺ > As³⁺

Answer : AD

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

(a) Its electronegativity is very high

(b) d-orbitals are available for bonding

(c) It is a typical non-metal

(d) Its molecular size is small

Answer : B

Question : Collectively the elements of group 15 are called –

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

Answer : A

Question : Which one of the following elements is most metallic ?

(a) P
(b) As
(c) Sb
(d) Bi

Answer : D

Question : Which of the following statement is incorrect for group 15 elements ?
(a) Order of ionization enthalpies is △iH₁ < △iH₂ < △iH₃
(b) The boiling point and melting point increases from top to bottom in the group
(c) Dinitrogen is a gas while all others are solids
(d) All statements are correct

Answer : B

Question : Which of the follow group 15 element forms metallic bonds in elemental state ?
(a) As
(b) P
(c) Sb
(d) Bi

Answer : D

Question : The three important oxidation states of phosphorus are
(a) –3, +3 and +5
(b) –3, +3 and –5
(c) –3, +3 and +2
(d) –3, +3 and +4

Answer : A

Question : Nitrogen is relatively inactive element because
(a) its atom has a stable electronic configuration
(b) it has low atomic radius
(c) its electronegativity is fairly high
(d) dissociation energy of its molecule is fairly high

Answer : D

Question : Which of the following has the highest pΠ – pΠ bonding tendency ?
(a) N
(b) P
(c) As
(d) Sb

Question : Pick out the wrong statement.
(a) Nitrogen has the ability to form pπ-pπ bonds with itself.
(b) Bismuth forms metallic bonds in elemental state.
(c) Catenation tendency is higher in nitrogen when compared with other elements of the same group.
(d) Nitrogen has higher first ionisation enthalpy when compared with other elements of the same group.

Answer : C

Question : Nitrogen forms N₂, but phosphorus is converted into P₄ from P, the reason is
(a) Triple bond is present between phosphorus atom
(b) pπ – pπ bonding is strong
(c) pπ – pπ bonding is weak
(d) Multiple bond is formed easily

Answer : C

Question : What causes nitrogen to be chemically inert ?
(a) Multiple bond formation in the molecule
(b) Absence of bond polarity
(c) Short internuclear distance
(d) High bond energy

Answer : D

Question : Among the 15^th group elements, as we move from nitrogen to bismuth, the pentavalency becomes less pronounced and trivalency becomes more pronounced due to
(a) Non metallic character
(b) Inert pair effect
(c) High electronegativity
(d) Large ionization energy

Answer : B

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

Answer : B

Question : Which one has the lowest boiling point ?
(a) NH₃
(b) PH₃
(c) AsH₃
(d) SbH₃

Answer : B

Question : Most acidic oxide among the following is –
(a) N₂O₅
(b) P₂O₅
(c) N2O₄
(d) As2O₃

Answer : A

Question : Which of the following species has the highest dipole moment?
(a) NH₃ 
(b) PH₃
(c) AsH₃ 
(d) SbH₃

Question : The correct decreasing order of basic strength is:

(a) AsH₃ > SbH₃ > PH₃ > NH₃

(b) SbH₃ > AsH₃ > PH₃ > NH₃

(c) NH₃ > PH₃ > AsH₃ > SbH₃

(d) PH₃ > AsH₃ > SbH₃ > NH₃

Answer : C

Question : Which of the following fluorides does not exist?
(a) NF₅
(b) PF₅
(c) AsF₅
(d) SbF₅

Answer : A

Question : The p-block element of group 15 that forms predominantly basic oxide is
(a) N
(b) P
(c) As
(d) Bi

Answer : D

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

(a) PH₃ is more basic than NH₃

(b) PH₃ is less basic than NH₃

(c) PH₃ is equally basic as NH₃

(d) PH₃ is amphoteric while NH₃ is basic

Answer : B

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 : A

Question : Maximum covalency of nitrogen is __________.

(a) 3
(b) 5
(c) 4
(d) 6

Answer : C

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) Bi₂O₅ 
(b) BiF₅
(c) BiCl₅
(d) Bi₂S₅

Answer : B

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

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

Answer : D

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) N₂O with ammonium dichromate and NO₂ with barium azide

Answer : A

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 : B

Question : Ammonia on reaction with hypochlorite anion can form :

(a) NO
(b) N₂H₄
(c) NH₄Cl
(d) Both (b) and (c)

Answer : D

Question : NH₃ gas is dried over :
(a) CaO
(b) HNO₃
(c) P₂O₅
(d) CuSO₄

Answer : A

Question : The shape of ammonia molecule is
(a) tetrahedral
(b) pyramidal
(c) planar triangle
(d) octahedral

Answer : B

Question : When ammonia is heated with cupric oxide, a molecule of ammonia will
(a) gain 3 electrons
(b) lose 3 electrons
(c) gain 2 electrons
(d) lose 2 electrons

Answer : B

Question : In which the NH₃ is not used ?

(a) Cold storage

(b) Anaesthetic

(c) Manufacture of rayon and plastic

(d) None of these

Answer : B

Question : Liquid ammonia bottles are opened after cooling them in ice for sometime. It is because liquid NH3

(a) Brings tears to the eyes

(b) Has a high vapour pressure

(c) Is a corrosive liquid

(d) Is a mild explosive

Answer : B

Question : Ammonia is generally manufactured for fertilizers by the reaction

(a) 2NH₄Cl + Ca(OH)₂ →CaCl₂ + 2H₂O + 2NH₃

(b) By passing an electric discharge in a mixture of N₂ and H₂

(c) By passing a mixture of N₂ and H₂ under high pressure and moderate temperature over a catalyst

(d) None of these

Answer : B

Question : Nitrogen dioxide cannot be obtained by heating :

(a) KNO₃
(b) Pb(NO₃)₂
(c) Cu(NO₃)₂
(d) AgNO₃

Answer : A

Question : Which of the following oxides is neutral ?

(a) N₂O₃
(b) N₂O₄
(c) N₂O₅
(d) N₂O

Answer : B

Question : The bonds present in N₂O₅ are :
(a) only ionic
(b) covalent and coordinate
(c) only covalent
(d) covalent and ionic

Answer : B

Question : Which of the following oxides of nitrogen is a coloured gas?
(a) N₂O
(b) NO
(c) N₂O₅
(d) NO₂

_{Answer : D}

Question :  Which one of the following is not an use of ammonia ?
(a) To produce various nitrogenous fertilizers.
(b) In manufacture of nitric acid
(c) As a refrigerate
(d) In the pickling of stainless steel

Answer : D

Question : In which one of the following oxides of nitrogen, one nitrogen atom is not directly linked to oxygen?
(a) NO
(b) N₂O₄
(c) N₂O
(d) N₂O₃

Answer : C

Question : Which of the following oxides of nitrogen reacts with FeSO₄ to form a dark brown compound
(a) N₂O
(b) NO
(c) NO₂
(d) N2O₃

Answer : B

Question : Which oxide of nitrogen is obtained on heating ammonium nitrate at 250ºC ?
(a) Nitric oxide
(b) Nitrous oxide
(c) Nitrogen dioxide
(d) Dinitrogen tetraoxide

Answer : B

Question : Which of the following can be used as an anaesthesia ?
(a) N₂O
(b) NO
(c) NCl₃
(d) NO₂

Answer : A

Question : A deep brown gas is formed by mixing two colourless gases which are
(a) NO₂ and O₂
(b) N₂O and NO
(c) NO and O₂
(d) NH₃ and HCl

Answer : C

Question : Which of the following elements does not form stable diatomic molecules ?
(a) Iodine
(b) Phosphorus
(c) Nitrogen
(d) Oxygen

Answer : B

Question : The catalyst used in the manufacture of HNO₃ by Ostwald’s process is :
(a) platinum gauze
(b) vanadium pentoxide
(c) finely divided nickel
(d) platinum black .

Answer : A

Question : Concentrated nitric acid, upon long standing, turns yellow brown due to the formation of
(a) NO
(b) NO₂
(c) N₂O
(d) N₂O₄

Answer : B

Question :  Which of the following trihalide is unstable?
(a) NF₃`
(b) AsCl₃
(c) SbBr₃ 
(d) NCl₃

_{Answer : D}

Question :  Which of the following element will form acidic oxides of type E₂O₃?
(a) As
(b) Sb
(c) Bi
(d) P 

Answer : D

Question : Which of the following is the strongest reducing agent ?
(a) NH₃
(b) PH₃
(c) BiH₃
(d) SbH₃

Answer : C