CBSE Class 12 Chemistry The p Block Elements Questions

Consequences :

1. The first element in p-block element has four valence orbitals i.e. one 2s and three 2p, Hence maximum covalency of the first element in limited to four. The other elements of the p-block elements have vacant d-orbitals in their valence shell, e.g. elements of the third period have nine (9) one 3s, three 3p and five three 3d orbitals. Hence these show maximum covalence greater than four. Following questions can be answered -

(i) Nitrogen (N) does not from pentahalide while P froms PCl₅, PF₅, and PF₆ –. Why?

(ii) Sulphur (S) forms SF6 but oxygen does not form OF₆. Why?

(iii) Though nitrogen forms pentoxide but it does not form pentachloride. Explain. Why?

(iv) Fluorine forms only one oxoacid while other halogens form a number of oxoacids. Why?

(2) The first member of p-block elements displays greater ability to from p_Π- p_Π bond (s) with itself, (e.g., C = C, C ≡ C, N = N, N ≡ N) and with the other elements of second period (e.g., C = O, C ≡ N, N = O) compared to the subsequent members of the group.

This is because p-orbitals of the heavier members are so large and diffuse that they cannot have effective sideways overlapping. Heavier members can form p_Π – d_Π bonds with oxygen.

Question. When Cl₂ gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from
(a) zero to +1 and zero to –5
(b) zero to –1 and zero to +5
(c) zero to –1 and zero to +3
(d) zero to +1 and zero to –3 

Question. Which of the following is used in the preparation of chlorine?
(a) Both MnO₂ and KMnO₄
(b) Only KMnO₄
(c) Only MnO₂
(d) Either MnO₂ or KMnO₄ 

Question. Which of the following elements is extracted commercially by the electrolysis of an aqueous solution of its compound?
(a) Cl
(b) Br
(c) Al
(d) Na 

Question. When chlorine is passed over dry slaked lime at room temperature, the main reaction product is
(a) Ca(ClO₂)₂
(b) CaCl₂
(c) CaOCl₂
(d) Ca(OCl)₂ 

Question. In the manufacture of bromine from sea water, the mother liquor containing bromides is treated with
(a) carbon dioxide
(b) chlorine
(c) iodine
(d) sulphur dioxide.

Question. The bleaching action of chlorine is due to
(a) reduction
(b) hydrogenation
(c) chlorination
(d) oxidation. 7.20 Hydrogen Chloride

Question. Bleaching powder reacts with a few drops of conc. HCl to give
(a) chlorine
(b) hypochlorous acid
(c) calcium oxide
(d) oxygen.

Question. Among the following, the correct order of acidity is
(a) HClO₂ < HClO < HClO₃ < HClO₄
(b) HClO₄ < HClO₂ < HClO < HClO₃
(c) HClO₃ < HClO₄ < HClO₂ < HClO
(d) HClO < HClO₂ < HClO₃ < HClO₄

Question. Which of the statements given below is incorrect?
(a) O3 molecule is bent.
(b) ONF is isoelectronic with O₂N–.
(c) OF₂ is an oxide of fluorine.
(d) Cl₂O₇ is an anhydride of perchloric acid.

Question. The correct order of increasing bond angles in the following species is
(a) Cl₂O < ClO₂ < ClO₂–
(b) ClO₂ < Cl₂O < ClO₂–
(c) Cl₂O < ClO₂– < ClO₂
(d) ClO₂– < Cl₂O < ClO₂ 

Question. Which one of the following oxides is expected to exhibit paramagnetic behaviour?
(a) CO₂
(b) SiO₂
(c) SO₂
(d) ClO₂

Question. Identify the incorrect statement, regarding the molecule XeO₄.
(a) XeO₄ molecule is square planar.
(b) There are four pp - dp bonds.
(c) There are four sp₃ - p, s bonds.
(d) XeO₄ molecule is tetrahedral.

Question. Which compound has planar structure?
(a) XeF₄
(b) XeOF₂
(c) XeO₂F₂
(d) XeO₄

Question. The ion or group detected by K₂[HgI₄] is :
(a) NO
(b) Cl^– 
(c) NH₂–
(d) NH⁴⁺

Question. Which gas cannot be collected over water ?
(a) O₂
(b) PH₃ 
(c) N₂
(d) SO₂

Question. H₂S does not produce metallic sulphide with :
(a) CuCl₂
(b) COCl₂ 
(c) CdCl₂
(d) ZnCl₂

Please refer to the link below for CBSE Class 12 Chemistry The p Block Elements Questions.