CBSE Class 12 Chemistry The p Block Elements MCQs Set 05

Question: The element evolving two different gases on reaction with cone. sulphuric acid is 
(a) P
(b) C
(c) Hg
(d) S
(e) Sn
Answer: b

Question: The atomicity of phosphorus is X and the PPP bond angle in the molecule is Y. What are X and Y? 
(a) X = 4, Y = 90°
(b) X = 4, Y = 60°
(c) X = 3, Y = 120°
(d) X = 2, Y = 180°
Answer: b

Question: Which of the following is not a peroxy acid? 
(a) Perphosphoric acid
(b) Pernitric acid
(c) Perdisulphuric acid
(d) Perchloric acid
Answer: d

Question: Sodium pyrophosphate is represented by which of the following fonnula ? 
(a) Na₂P₂O₄
(b) Na₄P₂O₅
(c) Na₄P₂O₇
(d) Na₂P₂O₅
Answer: c

 Question: The catalyst used in the manufacture of anunonia is
(a) V₂O₅
(b) Pt 
(c) Fe
(d) Ni(CO)₄
Answer: c

Question: Extrapure N₂ canbeobtainedbyheating
(a) NH₃ with CuO
(b) NH₄NO₃
(c) (NH₄)₂Cr₂O₇
(d) Ba(N₃)₂
Answer: d

Question: Concentrated mtr1c acid, upon long standing, turns yellow-brown due to the fonnation of 
(a) NO
(b) NO₂
(c) N₂O
(d) N₂O₄
Answer: b

Question: Pnicogens are the elements of group 
(a) 15
(b) 13
(c) 8
(d) zero
Answer: a

Question: In the electrothermal process, the compound displaced by silica from calcium phosphate is 
(a) calcium phosphide
(b) phosphine
(c) phosphorus
(d) phosphorus pentoxide
Answer: d

Question: Ammonia is dried over 
(a) slaked lime
(b) calcium chloride
(c) phosphorus pentoxide
(d) quicklime
Answer: d

Question: Which one of the following oxides of nitrogen dimerises into a colourless solid/liquid on cooling ? 
(a) N₂O
(b) NO
(c) N₂O₃
(d) NO₂
(e) N₂O₅
Answer: d

Question: Phosphorns pentoxide is widely used as 
(a) bleaching agent
(b) dehydrating agent
(c) oxidising agent
(d) reducing agent
Answer: b

Question: The molecule BF₃ and NF₃ both are covalent compounds, but BF₃ is non-polar and NF₃ is polar.
The reason is that
(a) boron is a metal and nitrogen is a gas in uncombined state
(b) BF₃ bonds have no dipole moment whereas NF₃ bond have dipole moment
(c) atomic size of boron is smaller than that of nitrogen 
(d) BF₃ is symmetrical molecule whereas NF₃ is unsymmetrical
Answer: d

Question: Soid PCl₅ exists as 
(a) PCl⁺₄
(b) PCI₅
(c) PCl⁺₄ and PCI^–₆
(d) PCI^–₆
Answer: c

Question: The reaction ofP4 with X leads selectively to P₄O₆ . The Xis
(a) dry O₂
(b) a mixture of O₂ and N₂
(c) moist O₂
(d) O₂ in the presence of aqueous NaOH
Answer: b

Question: The statements that is not con-ect is 
(a) hypophosphorous acid reduces silver nitrate to silver
(b) in solid state PCI₅ exists as [PCI₄]⁺ [PCI₆]^–
(c) pure phosphine is non-inflammable
(d) phosphorus acid on heating disproportionates to give metaphosphoric acid and phosphine
Answer: c

Question: The nitrite ion in represented by
I. [O-N=O]^Θ II. [N=O-O]^Θ
Which of the structures represents possible resonance fon-ns of this ion ? 
(a) Only I
(b) Only II
(c) Both I and II
(d) Neither I and I
Answer: a

Question: Which has the smallest size ?
(a) Na⁺
(b) Mg²⁺
(c) AI³⁺
(d) p⁵⁺
Answer: d

Question: The product formed in the reaction of SOCI₂ with white phosphorus is 
(a) PCI₃
(b) SO₂Cl₂
(c) SCl₂
(d) POCI₃
Answer: a 

Question: The reaction of white phosphorus with aqueous NaOH gives phosphine along with another phosphorus containing compound. The reaction type, the oxidation states of phosphorus in phosphine and the other product are respectively 
(a) redox reaction, – 3 and – 5
(b) redox reaction, 3 and + 5
(c) disproportionation reaction, – 3 and + 5
(d) disproportionation reaction, – 3 and + 3
Answer: c

Question: The least stable hydride of 15th group elements is
(a) NH₃
(b) PH₃
(c) AsH₃ 
(d) SbH₃
(e) BiH₃
Answer: e

Question: The most abundant element in the earth crust is 
(a) O
(b) Si
(c) H
(d) C
Answer: a

Question: Which of the following oxyacids of phosphorus is a reducing agent and monobasic ? 
(a) H₃PO₂
(b) H₃PO₃
(c) H₃PO₄
(d) H₄P₂O₆
Answer: a

Question: Which of the following(s) when heated give nitrogen gas?
(a) (NH₄)₂ Cr₂O₇
(b) Ba(N₃)₂
(c) NH₄NO₃
(d) Both (a) and (b)
Answer: d

Question: If an allotropic form changes slowly to a stable form. It is called 
(a) enantiotropy
(b) dynamic allotropy
(c) monotropy
(d) None of these
Answer: c

Question: Which of the element of nitrogen family produce maximum number of oxyacids ? 
(a) N
(b) P
(c) As
(d) Sb
Answer: b

Question: As the number of – OH groups increases in hypophosphorus acid, phosphorus acid and phosphoric acid, the acidic strength 
(a) increases
(b) decreases
(c) remains nearly same
(d) remains appropriately same
Answer: c

Question: Pb reacts with dilute HNO₃ gives 
(a) NO
(b) NH₄NO₃
(c) N₂O₅
(d) NO₂
Answer: a

Question: The following are some statements related to VA group hydrides.
I. Reducing property increases from NH₃ to BiH₃.
II. Tendency to donate lone pair decreases from NH₃ to BiH₃.
III. Thermal stability of hydrides decreases from NH₃ to BiH₃.
IV. Bond angle of hydrides decreases form NH₃ to BiH₃.
The con-ect statements are
(a) I, II, III and IV
(b) I, III and IV
(c) I, II and IV
(d) I and IV
Answer: a