p-Block Elements
- Given below are two statements :Statement I : Like nitrogen that can form ammonia, arsenic can form arsine.Statement II : Antimony cannot form antimony pentoxide.In the light of the above statements, choose the most appropriate answer from the option… Answer: 3. Statement I is correct but Statement II is incorrect Key idea: group 15 elements form hydrides EH₃ and oxides E₂O₅ . Statement I... 1
- The products A and B obtained in the following reactions, respectively, are3ROH + PCl_3 → 3RCl + AROH + PCl_5 → RCl + HCl + B Answer: 1. H₃PO₃ and POCl₃ Key idea: phosphorus halides convert ROH into RCl, and the phosphorus part ends as an acid or oxychloride. 3ROH+P... 1
- Given below are two statements:Statement I : The boiling point of hydrides of Group 16 elements follow the orderH_2O > H_2Te > H_2Se > H_2S.Statement II : On the basis of molecular mass, H_2O is expected to have lower boiling point than the other mem… Answer: 2. Both Statement I and Statement II are true. Key idea: boiling point of hydrides depends on H-bonding and on molecular mass. H₂O i... 1
- Among Group 16 elements, which one does NOT show -2 oxidation state? Answer: 1. Po Key idea: metallic character increases down the group, so the -2 state becomes unfavourable. O, S, Se and Te form oxides, sulp... 1
- Given below are two statements :Statement I : The nutrient deficient water bodies lead to eutrophication.Statement II : Eutrophication leads to decrease in the level of oxygen in the water bodies.In the light of the above statements, choose the corre… Answer: 1. Statement I is incorrect but Statement II is true. Key idea: Eutrophication is caused by nutrient enrichment. Statement I is fals... 1
- Match List - I with List - II :List - I (Oxoacids of Sulphur): A. Peroxodisulphuric acid B. Sulphuric acid C. Pyrosulphuric acid D. Sulphurous acidList - II (Bonds): I. Two S-OH, Four S=O, One S-O-S II. Two S-OH, One S=O III. Two S-OH, Four S=O, One… Answer: 3. A-III, B-IV, C-I, D-II Key idea: Draw the structure of each oxoacid. A. H₂S₂O₈ , peroxodisulphuric: two S-OH, four S=O and one S-... 1
- Taking stability as the factor, which one of the following represents correct relationship? Answer: 1. TlI > TlI ₃ Key idea: In group 13 the +1 state becomes more stable down the group because of the inert pair effect; for Tl, +1 is... 1
- Match List - I with List - II :List - I: A. Coke B. Diamond C. Fullerene D. GraphiteList - II: I. Carbon atoms are sp^3 hybridised. II. Used as a dry lubricant III. Used as a reducing agent IV. Cage like moleculesChoose the correct answer from the op… Answer: 4. A-III, B-I, C-IV, D-II Key idea: Match each form of carbon with its structure or use. A. Coke is used as a reducing agent in meta... 1
- The pollution due to oxides of sulphur gets enhanced due to the presence of :(a) particulate matter(b) ozone(c) hydrocarbons(d) hydrogen peroxideChoose the most appropriate answer from the options given below : Answer: 3. (a), (b), (d) only Key idea: SO₂ is converted to SO₃ and then to sulphuric acid faster when oxidants or surfaces are present. Par... 1
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) : ICl is more reactive than I_2.Reason (R) : I-Cl bond is weaker than I-I bond.In the light of the above statements, choose the mo… Answer: 2. Both (A) and (R) are correct and (R) is the correct explanation of (A) Key idea: interhalogen compounds are more reactive than th... 1
- Match List - I with List - II.List - I (Hydrides): (a) MgH_2 (b) GeH_4 (c) B_2H_6 (d) HFList - II (Nature): (i) Electron precise (ii) Electron deficient (iii) Electron rich (iv) IonicChoose the correct answer from the options given below : Answer: 2. (a) - (iv), (b) - (i), (c) - (ii), (d) - (iii) Key idea: classify hydrides by electron count. MgH₂ : metal hydride of s-block, io... 1
- Given below are two statements :Statement I :The boiling points of the following hydrides of group 16 elements increases in the order -H_2O < H_2S < H_2Se < H_2Te.Statement II :The boiling points of these hydrides increase with increase in molar mass… Answer: 3. Both Statement I and Statement II are incorrect. Key idea: water has an abnormally high boiling point because of hydrogen bonding... 1
- Which of the following statement is not correct about diborane ? Answer: 1. Both the Boron atoms are sp² hybridised. Key idea: in diborane each boron is sp³ hybridised, not sp² . Each B uses four sp³ orbit... 1
- Choose the correct statement : Answer: 4. Diamond is sp³ hybridised and graphite is sp² hybridized. Key idea: diamond and graphite are both covalent forms of carbon with d... 1
- Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is : Answer: 4. Beryllium chloride Key idea: small, highly polarising mathrmBe²⁺ gives strong covalent character (Fajans' rules). BeCl₂ is covale... 1
- Noble gases are named because of their inertness towards reactivity. Identify an incorrect statement about them. Answer: 2. Noble gases have very high melting and boiling points. Key idea: noble gases are monoatomic and held only by very weak dispersion... 1
- Which of the following is not correct about carbon monoxide ? Answer: 3. The carboxyhaemoglobin (haemoglobin bound to CO) is less stable than oxyhaemoglobin. CO binds to haemoglobin to form carboxyhaemo... 1
- Match the following and identify the correct option.(a) CO(g) + H_2(g) (i) Mg(HCO_3)_2 + Ca(HCO_3)_2(b) Temporary hardness of water (ii) An electron deficient hydride(c) B_2H_6 (iii) Synthesis gas(d) H_2O_2 (iv) Non-planar structure Answer: 1. (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv) (a) CO+H₂ is water gas, called synthesis gas: (iii). (b) Temporary hardness is due to Mg(H... 1
- Identify the correct statements from the following :(a) CO_2(g) is used as refrigerant for ice-cream and frozen food.(b) The structure of C_60 contains twelve six carbon rings and twenty five carbon rings.(c) ZSM-5, a type of zeolite, is used to conv… Answer: 4. (c) and (d) only Check each statement. (a) Solid CO₂ (dry ice) is the refrigerant for ice-cream and frozen food, not the gas. The... 1
- Which of the following oxoacid of sulphur has -O-O- linkage ? Answer: 3. H ₂ S ₂ O ₈ , peroxodisulphuric acid The peroxo linkage -O-O- is present in peroxoacids. H₂S₂O₈ (peroxodisulphuric acid, Marshall... 1
- Which of the following species is not stable ? Answer: 4. [SiCl₆]²⁻ Key idea: silicon (period 3) can expand its octahedral coordination, but only with small ligands. mathrm[SiF₆]²⁻ is kno... 1
- Identify the incorrect statement related to PCl_5 from the following : Answer: 4. PCl ₅ molecule is non-reactive PCl₅ is trigonal bipyramidal. Three equatorial P-Cl bonds are at 120 to each other: correct. Two a... 1
- Match the Xenon compounds in Column - I with its structure in Column - II and assign the correct code :Column - I: (a) XeF_4 (b) XeF_6 (c) XeOF_4 (d) XeO_3Column - II: (i) pyramidal (ii) square planar (iii) distorted octahedral (iv) square pyramidalC… Answer: 2. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i) (a) XeF₄ : square planar, (ii) (b) XeF₆ : distorted octahedral, (iii) (c) XeOF₄ : square p... 1
- Among the following, the one that is not a green house gas is : Answer: 4. sulphur dioxide Greenhouse gases absorb infrared radiation re-emitted by the Earth. N₂O , CH₄ and O₃ (and CO₂ , CFCs) all do. SO₂... 1