CBSE Class 12 Chemistry The p Block Elements MCQs Set C

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. Which of the following statement 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. Urea reacts with water to form A which will decompose to form B. B when passed through Cu²⁺ (aq), deep blue colour solution C is formed. What is the formula of C from the following?
(a) CuSO₄
(b) [Cu(NH₃)₄]²⁺
(c) Cu(OH)₂
(d) CuCO₃·Cu(OH)₂

Answer : B

Question. Aqueous solution of ammonia consists of
(a) H⁺
(b) OH^–
(c) NH⁴⁺
(d) NH⁴⁺ and OH^–.

Answer : D

Question. Which of the following oxides of nitrogen is paramagnetic?
(a) NO₂
(b) N₂O₃
(c) N₂O
(d) N₂O₅

Answer : A

Question. Argon is used
(a) in filling airships
(b) to obtain low temperature
(c) in high temperature welding
(d) in radiotherapy for treatment of cancer

Answer : C

Question. Each of the following is true for white and red phosphorus except that they
(a) are both soluble in CS₂
(b) can be oxidised by heating in air
(c) consist of the same kind of atoms
(d) can be converted into one another.

Answer : A

Question. A compound ‘X’ upon reaction with H₂O produces a colourless gas ‘Y’ with rotten fish smell. Gas ‘Y’ is absorbed in a solution of CuSO₄ to give Cu₃P₂ as one of the products. Predict the compound ‘X’.
(a) Ca₃P₂
(b) NH₄Cl
(c) As₂O₃
(d) Ca₃(PO₄)₂

Answer : A

Question. PH₄I + NaOH forms
(a) PH₃
(b) NH₃
(c) P₄O₆
(d) P₄O₁₀

Answer : A

Question. Identify the incorrect statement related to PCl₅ from the following :
(a) PCl₅ molecule is non-reactive.
(b) Three equatorial P – Cl bonds make an angle of 120° with each other.
(c) Two axial P – Cl bonds make an angle of 180° with each other.
(d) Axial P – Cl bonds are longer than equatorial P – Cl bonds.

Answer : A

Question. P₂O₅ is heated with water to give
(a) hypophosphorous acid
(b) phosphorous acid
(c) hypophosphoric acid
(d) orthophosphoric acid.

Answer : D

Question. Basicity of orthophosphoric acid is
(a) 2
(b) 3
(c) 4
(d) 5

Answer : B

Question. Among the following oxides, the lowest acidic is
(a) As4O₆
(b) As4O₁₀
(c) P₄O₆
(d) P₄O₁₀ 

Answer : A

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

Answer : A

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

Answer : B

Question. Number of electrons shared in the formation of nitrogen molecule is
(a) 6
(b) 10
(c) 2
(d) 8

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. Strong reducing behaviour of H₃PO₂ is due to
(a) high electron gain enthalpy of phosphorus
(b) high oxidation state of phosphorus
(c) presence of two —OH groups and one P—H bond
(d) presence of one —OH group and two P—H bonds.

Answer : D

Question. Which of the following statements is not valid for oxoacids of phosphorus?
(a) Orthophosphoric acid is used in the manufacture of triple superphosphate.
(b) Hypophosphorous acid is a diprotic acid.
(c) All oxoacids contain tetrahedral four coordinated phosphorus.
(d) All oxoacids contain atleast one P O unit and one P—OH group.

Answer : B

Question. Oxidation states of P in H₄P₂O₅, H₄P₂O₆, H₄P₂O₇ are respectively
(a) +3, +5, +4
(b) +5, +3, +4
(c) +5, +4, +3
(d) +3, +4, +5

Answer : D

Question. Which of the following is a nitric acid anhydride?
(a) NO
(b) NO₂
(c) N₂O₅
(d) N₂O₃

Answer : C

Question. When copper is heated with conc. HNO₃ it produces
(a) Cu(NO₃)₂, NO and NO₂
(b) Cu(NO₃)₂ and N₂O
(c) Cu(NO₃)₂ and NO₂
(d) Cu(NO₃)₂ and NO 

Answer : C

Question. Zn gives H₂ gas with H₂SO₄ and HCl but not with HNO₃ because
(a) Zn act as oxidising agent when react with HNO₃
(b) HNO3 is weaker acid than H₂SO₄ and HCl
(c) in electrochemical series Zn is above hydrogen
(d) NO₃– is reduced in preference to hydronium ion

Answer : D

Question. Sugarcane on reaction with nitric acid gives
(a) CO₂ and SO₂
(b) (COOH)₂
(c) 2HCOOH(two moles)
(d) no reaction. 

Answer : B

Question. Which of the following phosphorus is the most reactive?
(a) Scarlet phosphorus
(b) White phosphorus
(c) Red phosphorus
(d) Violet phosphorus

Answer : B

Question. Aqua-regia is
(a) 1 : 3 cone. HNO₃ and cone. HCl
(b) 1 : 2 cone. HNO₃ and cone. HCl
(c) 3 : 1 conc. HNO₃ and cone. HCl
(d) 2 : 1 cone. HNO₃ and cone. HCl

Answer : A

Question. Which of the following pair have identical shape ?
(a) CH₄ , SF₄
(b) BCI₃ , ClF₃
(c) XeF₂, ZnCl₂
(d) SO₂ , CO₂ 

Answer : C

Question. The molecular ion XF₂ bas three pairs of non-bonding electrons around the central atom. The bond angle F—X—F will be closest to
(a) 180°
(b) 120°
(c) 109°
(d) 90°

Answer : A

Question. Which of the following pairs contains isoelectronic species ?
(a) Be and Li⁺
(b) p⁺ and s^–
(c) N^2- and Ne
(d) O^2- and Na⁺

Answer : D

Question. Which is the correct statement for the given acids?
(a) Phosphinic acid is a monoprotic acid while phosphonic acid is a diprotic acid.
(b) Phosphinic acid is a diprotic acid while phosphonic acid is a monoprotic acid.
(c) Both are diprotic acids.
(d) Both are triprotic acids.

Answer : A