s-Block Elements PYQs Set 15 (PDF)

Set 15 of 20 · Questions 421-450 of 573

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Mere Teacher · Previous Year Questions NEET Chemistry · s-Block Elements · Set 15 (Q421-450)
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421. $Which one of the following is true?$ (1) $NaOH is used in the concentration of bauxite ore.$ (2) $NaOH is a primary standard in volumetric analysis.$ (3) $Manganous hydroxide is soluble in excess of NaOH solution.$ (4) $NaOH solution does not react with Cl_{2} .$ 422. $Consider the following statements. I. Cs^{+} ion is more highly hydrated than other alkali metal ions. II. Among the alkali metals, only lithium forms a stable nitride by direct combination with nitrogen. III. Among the alkali metals Li, Na, K, Rb, the metal, Rb has the highest melting point. IV. Among the alkali metals Li, Na, K, Rb, only Li forms peroxide when heated with oxygen. Select the correct statement is$ (1) $I$ (2) $II$ (3) $III$ (4) $IV$ 423. $Powdered beryllium burns in air to give$ (1) $BeO; Be_{2} N_{2}$ (2) $Be_{2} O_{3}; Be_{3} N_{2}$ (3) $BeO; Be_{3} N_{2}$ (4) $BeO; Be_{2} N$ 424. $Match the following: Column-I (Reaction) (A) FeCl_{3} (aq) + NH_{3} (aq) ⟶ (B) AgCl (aq) + NH_{3} (aq) ⟶ (C) Cu^{2 +} (aq) + NH_{3} (aq) ⟶ Column-II (Colour of the product or nature) (I) Green ppt (II) Deep blue (III) Brown ppt (IV) Colourless The correct answer is A B C$ (1) $I II III$ (2) $I III IV$ (3) $III IV II$ (4) $III I IV$ 425. $Hybridisation of boron in diborane is$ (1) $sp$ (2) $s p^{2}$ (3) $s p^{3}$ (4) $s p^{3} d$ 426. $Ozone is obtained from oxygen$ (1) $by oxidation at high temperature$ (2) $by oxidation using a catalyst$ (3) $by silent electric discharge$ (4) $by conversion at high pressure$ 427. $The incorrect statement is:$ (1) $Lithium is the strongest reducing agent among the alkali metals.$ (2) $Lithium is the least reactive with water among the alkali metals.$ (3) $LiNO_{3} decomposes on heating to give LiNO_{2} and O_{2} .$ (4) $LiCl crystallises from aqueous solution as LiCl . 2 H_{2} O .$ 428. $Which one of the following is correct?$ (1) $Thallium is more electropositive than aluminium$ (2) $Boron has high electrical conductivity$ (3) $An aqueous solution of ortho boric acid is generally used as a mild antiseptic$ (4) $Boron - 11 (^{11} B) isotope has high ability to absorb neutrons$ 429. $Which of the following is not correct?$ (1) $Lead does not show catenation$ (2) $Buckminster fullerene contains 20 six-membered rings and 12 five-membered rings$ (3) $Stability order of GeX_{2}, SnX_{2} and PbX_{2} is GeX_{2} < SnX_{2} < PbX_{2}$ (4) $The number of metalloids in group 14 elements is 2$ 430. $Chlorine is liberated when we heat :$ (1) $K M n O_{4} + NaCl$ (2) $K_{2} C r_{2} O_{7} + M n O_{2}$ (3) $Pb (N O_{3})_{2} + M n O_{2}$ (4) $K_{2} C r_{2} O_{7} + HCl$ 431. $Sulphur sol contains$ (1) $discrete S-atoms$ (2) $discrete S-molecules$ (3) $large aggregates of S -molecules$ (4) $water dispersed in solid sulphur.$ 432. $Ammonia can be dried by :$ (1) $conc. H_{2} S O_{4}$ (2) $P_{4} O_{10}$ (3) $CaO$ (4) $anhydrous C a C l_{2}$ 433. $Sea divers use a mixture of$ (1) $O_{2}, N_{2}$ (2) $O_{2}, H_{2}$ (3) $O_{2}, He$ (4) $N_{2}, H_{2}$ 434. $Which is true regarding nitrogen?$ (1) $Less electronegative$ (2) $Has low ionisation enthalpy$ (3) $d -orbitals are available$ (4) $Ability to form pπ - pπ bonds with itself$ 435. $The correct statement is$ (1) $BI_{3} is the weakest Lewis acid among the boron halides$ (2) $there is minimum pπ-pπ back bonding in BF_{3}$ (3) $BF_{3} is the strongest Lewis acid among the other boron halides$ (4) $there is maximum pπ-pπ back bonding in BF_{3} .$ 436. $Given below are two statements: One islabelled as Assertion A and the other labelledas reason R Assertion A : During the boiling of water having temporary hardness, Mg (HCO_{3})_{2} is converted to MgCO_{3} Reason R : The solubility product of Mg (OH)_{2} is greater than that of MgCO_{3} . choose the most appropriate answer from the options given below:$ (1) $Both A and R are true but R is not the correct explanation of A$ (2) $A is true but R is false$ (3) $Both A and R are true and R is the correct explanation of A$ (4) $A is false and R is also false$ 437. $Argon is used$ (1) $to obtain low temperature$ (2) $in high temperature welding$ (3) $in radiotherapy for treatment of cancer$ (4) $in filling airships.$ 438. $The formula of borax is$ (1) $Na_{2} B_{4} O_{7} \cdot 5 H_{2} O$ (2) $Na_{2} B_{4} O_{7} \cdot 7 H_{2} O$ (3) $Na_{2} B_{4} O_{7} \cdot 10 H_{2} O$ (4) $Na_{2} B_{4} O_{7} \cdot 2 H_{2} O$ 439. $Identify the correct statement.$ (1) $Plaster of Paris can be obtained by hydration of gypsum.$ (2) $Plaster of Paris is obtained by partial oxidation of gypsum.$ (3) $Gypsum contains a lower percentage of calcium than Plaster of Paris.$ (4) $Gypsum is obtained by heating Plaster of Paris.$ 440. $Phosphorus pentachloride$ (1) $on hydrolysis gives an oxo acid of phosphorus which is a good reducing agent$ (2) $has all the five equivalent bonds$ (3) $exists as an ionic solid in which cation has octahedral structure and anion has tetrahedral structure$ (4) $on hydrolysis gives an oxo acid of phosphorus which is tribasic.$ 441. $The products obtained on heating L i N O_{3} will be :$ (1) $L i_{2} O + N O_{2} + O_{2}$ (2) $L i_{3} N + O_{2}$ (3) $L i_{2} O + NO + O_{2}$ (4) $L i N O_{3} + O_{2}$ 442. $Which from following elements is in liquid state at room temperature?$ (1) $Se$ (2) $Br$ (3) $I$ (4) $s$ 443. $Which element from following rapidly loses it's luster in air and tarnishes?$ (1) $Ba$ (2) $Be$ (3) $K$ (4) $Mg$ 444. $Which one of the following forms a basic oxide?$ (1) $B$ (2) $Tl$ (3) $Al$ (4) $Ga$ 445. $The element that forms stable compounds in low oxidation state is$ (1) $Mg$ (2) $Al$ (3) $Ga$ (4) $Tl$ 446. $Among the following oxides, the one which is most basic is$ (1) $Z n O$ (2) $M g O$ (3) $A l_{2} O_{3}$ (4) $N_{2} O_{5}$ 447. $Phosphorous and phosphoric acids are, respectively,______acids.$ (1) $dibasic, tribasic$ (2) $tribasic, tribasic$ (3) $tribasic, dibasic$ (4) $tetrabasic, tribasic$ 448. $Assertion (A) : MgSO_{4} is readily soluble in waterReason (R) : The greater hydration enthalpy of Mg^{2 +} ions overcome its lattice enthalpy.$ (1) $A and R both are correct and R is the correct explanation of A .$ (2) $A and R both are correct but R is not the correct explanation of A .$ (3) $A is correct but R is not correct.$ (4) $A is incorrect but R is correct.$ 449. $The number of six membered carbon rings and five membered carbon rings present in Buckminster fullerene are x and y respectively. The sum of x and y is:$ (1) $32$ (2) $23$ (3) $30$ (4) $42$ 450. $One mole of magnesium nitride on the reaction with an excess of water gives :$ (1) $one mole of ammonia$ (2) $one mole of nitric acid$ (3) $two moles of ammonia$ (4) $two moles of nitric acid.$