CBSE Class 12 Chemistry The p Block Elements MCQs Set B

Question. In which of the following compounds, nitrogen exhibits highest oxidation state?
(a) N₂H₄
(b) NH₃
(c) N₃H
(d) NH₂OH

Answer : C

Question. Nitrogen forms N₂, but phosphorus does not form P₂, however, it converts P4, reason is
(a) triple bond present between phosphorus atom
(b) pp – pp bonding is weak
(c) pp – pp bonding is strong
(d) multiple bonds form easily.

Answer : B

Question. Which of the following oxides is most acidic?
(a) As₂O₅
(b) P₂O₅
(c) N₂O₅
(d) Sb₂O₅ 

Answer : C

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

Answer : C

Question. The basic character of hydrides of the V group elements decreases in the order
(a) NH₃ > PH₃ > AsH₃ > SbH₃
(b) SbH₃ > AsH₃ > PH₃ > NH₃
(c) SbH₃ > PH₃ > AsH₃ > NH₃
(d) NH₃ > SbH₃ > PH₃ > AsH₃ 

Answer : A

Question. Which of the following is most volatile ?
(a) HF
(b) HCI
(c) HBr
(d) HI

Answer : D

Question. Under ambient conditions, the total number of gases released as products in the final step of the reaction scheme shown below is

(a) 0
(b) 1
(c) 2
(d) 3

Answer : C

Question. Which one of the following is used for the separation of noble gas mixture from air ?
(a) Charcoal
(b) 90% CaC₂ + 10% CaCl₂
(c) Soda lime + potash solution
(d) 90% CaCO₃ + 10% urea

Answer : B

Question. In Ramsay and Rayleigh’s isolation of noble gases from air, the nitrogen of the air is finally converted into
(a) NaNO₂ only
(b) NO and NO₂
(c) NaNO₃ only
(d) NaNO₂ and NaNO₃

Answer : D

Question. Molecules of a noble gas do not posses vibrational energy because a noble gas
(a) is monoatomic
(b) is chemically inert
(c) has completely filled shells
(d) is diamagnetic

Answer : A

Question. Which of the following sets have correctly matched each molecule or ion and its geometry ?

Answer : B

Question. The unbalanced chemical reactions given in Column I show missing reagent or condition (?) which are provided in Column II. Match Column I with Column II and select the correct answer using the codes given below the columns.

      A    B     C    D    E
(a) 3     2     5     4     1
(b) 5     3     2     4     1
(c) 1     4     5     2     3
(d) 1     2     3     4     5

Answer : D

Question. When orthophosphoric acid is heated to 600°C, the product formed is
(a) PH₃
(b) P₂O₅
(c) H₃PO₃
(d) HPO₃

Answer : D

Question. Which is the correct thermal stability order for H2E (E = O, S, Se, Te and Po) ?
(a) H₂Se < H₂Te < H₂Po < H₂O < H₂S
(b) H₂S < H₂O < H₂Se < H₂Te <H₂Po
(c) H₂O < H₂S < H₂Se <H₂Te < H₂Po
(d) H₂Po < H₂Te < H₂Se < H₂S < H₂O

Answer : D

Question. Acidity of diprotic acids in aqueous solutions increases in the order
(a) H₂S < H₂Se < H₂Te
(b)H₂Se <H₂S < H₂Te
(c) H₂Te < H₂S < H₂Se
(d) H₂Se <H₂Te < H₂S

Answer : A

Question. Which of the following bonds has the highest energy?
(a) S–S
(b) O–O
(c) Se–Se
(d) Te–Te

Answer : A

Question. Which of the following does not give oxygen on heating?
(a) K₂Cr₂O₇
(b) (NH₄)2Cr₂O₇
(c) KClO₃
(d) Zn(ClO₃)₂

Answer : B

Question. The correct order of pseudohalide, polyhalide and interhalogen are
(a) BrI^–₂ , OCN^– , IF^–₅
(b) IF⁵ , BrI^–₂ , OCN^–
(c) OCN^– , IF₅ , BrI^–₂
(d) OCN- , BrI^–₂, IF₅

Answer : D

Question. The structure of XeF₆ is experimentally determined to be distorted octahedron. Its structure according to VSEPR theory is
(a) octahedron
(b) trigonal bi pyramid
(c) pentagonal bi pyramid
(d) tetragonal bipyramid

Answer : C

Question. Platinum, palladium and iridium are called noble metals because
(a) Alfred Nobel discovered them
(b) they are found in native state
(c) they are shining lustrous and pleasing to look at
(d) they are inert towards many common reagents

Answer : D

Question. Helium-oxygen mixture is used by deep sea divers in preference to nitrogen-oxygen mixture because
(a) helium is much less soluble in blood than nitrogen
(b) nitrogen is much less soluble in blood than helium
(c) due to high pressure deep under the sea nitrogen and oxygen react to give poisonous nitric oxide
(d) nitrogen is highly soluble in water

Answer : A

Question. The structure of XeOF₄ is
(a) trigonal bipyramidal
(b) square planar
(c) square pyramidal
(d) pyramidal

Answer : C

Question. Which of the following sets has the atoms and/or ions in the correct order of increasing size ?
(a) Ne < F^– < O^2-
(b) Br^– < Cl^– < F^–
(c) Na⁺ < Mg²⁺ < Al³⁺
(d) P < S < Cl

Answer : A

Question. Which of the following is the life saving mixture for an asthma patient?
(a) Mixture of helium and oxygen
(b) Mixture of neon and oxygen
(c) Mixture of xenon and nitrogen
(d) Mixture of argon and oxygen

Answer : A

Question. Which one of the following reaction of xenon compounds is not feasible?
(a) XeO₃ + 6HF → XeF₆ + 3H₂O
(b) 3XeF₄ + 6H₂O → 2Xe + XeO₃+ 12HF + 1.5 O₂
(c) 2XeF₂ + 2H₂O → 2Xe + 4HF + O₂
(d) XeF₆ + RbF → Rb[XeF₇ ]

Answer : A

Question. PCl₃ reacts with water to form
(a) PH₃
(b) H₃PO₃, HCl
(c) POCl₃
(d) H₃PO₄

Answer : B

Question. Which of the following oxoacids of phosphorus has strongest reducing property?
(a) H₄P₂O₇
(b) H₃PO₃
(c) H₃PO₂
(d) H₃PO₄

Answer : C

Question. Which one of the following substance is used in the laboratory for fast drying of neutral gases?
(a) Phosphorus pentoxide
(b) Active charcoal
(c) Anhydrous calcium chloride
(d) Na₃PO₄

Answer : A

Question. How many bridging oxygen atoms are present in P₄O₁₀?
(a) 6
(b) 4
(c) 2
(d) 5

Answer : A

Question. H₃PO₂ is the molecular formula of an acid of phosphorus. Its name and basicity respectively are
(a) phosphorous acid and two
(b) hypophosphorous acid and two
(c) hypophosphorous acid and one
(d) hypophosphoric acid and two.

Answer : C