s-Block Elements PYQs Set 10 (PDF)

Set 10 of 20 · Questions 271-300 of 573

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Mere Teacher · Previous Year Questions NEET Chemistry · s-Block Elements · Set 10 (Q271-300)
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271. $Which one of the following statements about allotropes of carbon is incorrect?$ (1) $Graphite is an electrical conductor but the conductivity is direction dependent.$ (2) $Diamond is more dense than graphite.$ (3) $Diamond is metastable.$ (4) $Graphite is thermodynamically less stable allotrope of carbon.$ 272. $Two elements A and B have similar chemical properties. They don't form solid hydrogencarbonates, but react with nitrogen to form nitrides. A and B, respectively, are$ (1) $Li and Mg$ (2) $Cs and Ba$ (3) $Na and Rb$ (4) $Na and Ca$ 273. $The correct order of the solubility of alkaline-earth metal sulphates in water is :$ (1) $Mg < Sr < Ca < Ba$ (2) $Mg > Ca > Sr > Ba$ (3) $Mg > Sr > Ca > Ba$ (4) $Mg < Ca < Sr < Ba$ 274. $Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : LiF is sparingly soluble in water. Reason R : The ionic radius of L i^{+} ion is smallest among its group members, hence has least hydration enthalpy. choose the most appropriate answer from the options given below .$ (1) $Both A and R are true and R is the correct explanation of A$ (2) $Both A and R are true but R is NOT the correct explanation of A$ (3) $A is true but R is false$ (4) $A is false but R is true$ 275. $In the reactions I and II the covalencies of Be and Al in X and Y are respectively I Be (OH)_{2} + NaOH \to X (excess) II Al (OH)_{3} + NaOH \to Y (excess)$ (1) $4,6$ (2) $4,4$ (3) $6,4$ (4) $3,6$ 276. $What is the correct order of melting temperature of C, Si, Ge ?$ (1) $C > Ge > Si$ (2) $Si > C > Ge$ (3) $C > Si > Ge$ (4) $Si > Ge > C$ 277. $What are the correct statements about the elements of group 13 given below? (I) The stability of +1 oxidation state follows the order T 1 > In > Ga (II) Boron has the lowest melting point and boiling point as it is a non-metal (III)Boron shows a maximum covalency of 4 in its compounds (IV) T The order of atomic radius is Ga > Al > In (V) Aluminium is passive to concentrated nitric acid$ (1) $I, III & V only$ (2) $II, IV & V only$ (3) $I, II & IV only$ (4) $III, IV & V only$ 278. $Assertion (A) : LiCl and MgCl_{2} are soluble in ethanol. Reason (R) : Lithium and magnesium are harder than their respective group elements. The correct option among the following is$ (1) $(A) is true, (R) is true and (R) is the correct explanation for (A) .$ (2) $(A) is true, (R) is true but (R) is not the correct explanation for (A) .$ (3) $(A) is true but (R) is false.$ (4) $(A) is false but (R) is true.$ 279. $Aluminium chloride in acidified aqueons solution gives a complex ion ' X'. The hybridization of central atom in X is$ (1) $s p^{3}$ (2) $s p^{2} d$ (3) $d^{2} s p^{3}$ (4) $s p^{3} d^{2}$ 280. $Among the following, the energy of 2s orbital is lowest in:$ (1) $K$ (2) $H$ (3) $Li$ (4) $Na$ 281. $The reaction of diborane in diethylether with X gives metalborohydride. X is a$ (1) $Metal$ (2) $Metal halide$ (3) $Metal hydride$ (4) $Metal oxide$ 282. $In the brown ring test, the brown colour of the ring is due to$ (1) $a mixture of NO and NO_{2}$ (2) $nitrosoferrous sulphate$ (3) $ferrous nitrate$ (4) $ferric nitrate.$ 283. $The solubility in water of sulphate down the Be group is Be > M g > C a > Sr > B a . This is due to$ (1) $decreasing lattice energy$ (2) $high heat of solvation for smaller ions like B e^{2 +}$ (3) $increase in melting points$ (4) $increasing molecular weight.$ 284. $Which of the following elements forms pπ - pπ bond with itself?$ (1) $N$ (2) $Te$ (3) $P$ (4) $Se$ 285. $Which one of the following statements regarding helium is incorrect ?$ (1) $It is used to produce and sustain powerful superconducting magnets$ (2) $It is used as a cryogenic agent for carrying out experiments at low temperatures$ (3) $It is used to fill gas balloons instead of hydrogen because it is lighter and non-inflammable$ (4) $It is used in gas-cooled nuclear reactors$ 286. $The alkaline earth metal nitrate that does not crystallise with water molecules, is:$ (1) $Mg (N O_{3})_{2}$ (2) $Sr (N O_{3})_{2}$ (3) $Ca (N O_{3})_{2}$ (4) $Ba (N O_{3})_{2}$ 287. $Which of the following statements are correct? A. The isotope of carbon containing 7 neutrons has natural abundance of 1.1 % B. Among the IVA group elements, Sn has the lowest melting point C. Silicon is the 2nd (by mass) most abundant element in the Earth's crust D. Element carbon shows the highest electrical resistivity among the 14 group elements.$ (1) $A, C and D$ (2) $A, B and C$ (3) $B, C and D$ (4) $A, B, C and D$ 288. $Assertion (A) : The ionic radii of the alkaline earth metals are smaller than those of alkali metals in the same period.Reason (R) : Alkali metals have higher nuclear charge than that of the alkaline earth metals.The correct option among the following is$ (1) $(A) is true, (R) is true and (R) is the correct explanation for (A)$ (2) $(A) is true, (R) is true but (R) is not the correct explanation for (A)$ (3) $(A) is true but (R) is false$ (4) $(A) is false but (R) is true$ 289. $BF_{3} is used as a catalyst in several industrial processes due to its$ (1) $strong reducing nature.$ (2) $weak reducing action$ (3) $strong Lewis acid nature$ (4) $weak Lewis acid character$ 290. $Arrange the hydrides NH_{3}, HF, H_{2} O, HCl in the increasing order of their boiling points$ (1) $HF < NH_{3} < HCl < H_{2} O$ (2) $H_{2} O < HF < HCl < NH_{3}$ (3) $NH_{3} < HCl < H_{2} O < HF$ (4) $HCl < NH_{3} < HF < H_{2} O$ 291. $Assertion (A): The bond dissociation energy increases from F_{2} to Cl_{2} and then decreases to I_{2} . Reason (R): The low bond energy of fluorine is due to the repulsion between the lone pairs of electrons in two fluorine atoms.$ (1) $Both A and R are true and R is the correct explanation of A .$ (2) $Both A and R are true but R is not the correct explanation of A .$ (3) $A is true but R is false.$ (4) $A is false but R is true.$ 292. $Identify the incorrect statement about the oxidation states of group 14 elements$ (1) $Carbon and Silicon mostly exhibit +4 oxidation state$ (2) $Tin in +2 oxidation state is a reducing agent$ (3) $Lead in +2 oxidation state is a reducing agent$ (4) $The order of stability of +2 oxidation state follow the sequence Ge < Sn < Pb$ 293. $The metal that gives hydrogen gas upon treatment with both acid as well as base is:$ (1) $magnesium$ (2) $mercury$ (3) $zinc$ (4) $iron$ 294. $Which one of the alkali metals, forms only, the normal oxide, M_{2} O on heating in air?$ (1) $Rb$ (2) $K$ (3) $Li$ (4) $Na$ 295. $Equimolar solutions of the following were prepared in water separately. Which one of the solutions will record the highest p H ?$ (1) $M g C l_{2}$ (2) $C a C l_{2}$ (3) $S r C l_{2}$ (4) $B a C l_{2}$ 296. $Which factor makes Li the strongest reducing agent in aqueous solution?$ (1) $Sublimation enthalpy$ (2) $lonization enthalpy$ (3) $Hydration enthalpy$ (4) $Electron gain enthalpy$ 297. $Choose the correct statement from the following with reference to inert pair effect$ (1) $Sn^{+ 4} is reducing agent but Pb^{+ 4} is an oxidizing agent$ (2) $Sn^{+ 4} is an oxidizing agent but Pb^{+ 2} is a reducing agent$ (3) $Sn^{+ 2} is reducing agent but Pb^{+ 4} is an oxidizing agent$ (4) $Sn^{+ 2} is an oxidizing agent but Pb^{+ 4} is a reducing agent$ 298. $Which among the following is least covalent in nature?$ (1) $NF_{3}$ (2) $BiF_{3}$ (3) $PF_{3}$ (4) $SbF_{3}$ 299. $Formic acid is heated with conc. H_{2} SO_{4} at 100^{\circ} C to form A and B . When Fe_{2} O_{3} is heated strongly with B, the products formed are C and D . C can also be obtained by reacting CaCO_{3} with dil. HCl . What is D ?$ (1) $F e$ (2) $CO$ (3) $CO_{2}$ (4) $Fe_{3} O_{4}$ 300. $The complex formed when Al_{2} O_{3} is leached from bauxite using concentrated NaOH solution is$ (1) $Na (Al (OH)_{4})$ (2) $NaAl_{2} O_{4}$ (3) $Na_{2} (Al (OH)_{3})$ (4) $Na_{2} AlO_{2}$