Unit14 s-block elements qns

Unit14 s-block elements qns - 1 UNIT 14 IA AND IIA OR...

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1 QUEST TUTORIALS Head Office : E-16/289, Sector-8, Rohini, New Delhi, Ph. 65395439 UNIT 14 IA AND IIA OR GROUPS 1 AND 2 : S-BLOCK ELEMENTS (Alkali metals; Alkaline earth metals) Select the lettered item which best completes each of the following: 1. The outer shell electronic configuration of Cs (Z =55) (a) [Ne] 3 S 1 (b) [Ar] 4 S 1 (c) [kr] 5 S 1 (d) [Xe] 6 S 1 2. The last electron has the quantum numbers n = 5, l =0, m =0, s = +1/2. the atomic numbe of the element is (a) 19 (b) 37 (c) 55 (d) 11 3. Alkali metals areusually prepared by (a) reduction of their oxides by carbon (b) reduction of their oxides with Al (c) electrolysis of their molten chlorides (d) thermal decomposition of their carbonates 4. Which compound possesses the highest lattice energy? (a) CsI (b) KF (c) LiF (d) NaCl 5. Which of the following compounds has the highest melting point ? (a) NaF (b) NaCl (c) NaBr (b) NaI 6. The alkali metals are strong reducing agents due to (a) low ionization energy (b) large ionic radii (c) high enthalpy of hydration (d) potential value 7. The covalent radius of the potassium atom is 0.203 manometer. The radius of K + ion will be (a) 0.013 (b) 0.254 (c) 0.133 (d) 0.231 8. Which one of the following has lowest first ionization energy? (a) Li (b) Na (c) Rb (d) Cs 9. Li (s) Li + (aq) + e , Eº = 3.67V, Li is the best reducing agent due to its (a) low I.E. (b) small ionic radius (c) low heat of sublimation of Li (d) high enthalpy of bydration of Li + 10. The physical property of the group IA metals which increases numericaly as the groupis descended is (a) first I.E. (b) ionic radii (c) melting point (d) hydration enthalpy of M + ions 11. Which of the following does not produce an alkaline solution in water? (a) NaHCO 3 (b) NaOH (c) Na 2 CO 3 (d) NaHSO 4 12. Which one of the following concerning the compounds of Lithium is false ? (a) the hydroxide, carbonate, nitrate decomposes to give the oxide on heating (b) it is the most electro- negative element of group IA (c) the hydrogen carbonate cannot be isolated as a stable solid (d) it forms a peroxide but not a superoxide 13. Which alkali metal has the lowest melting point and exists as aliquid ? (a) Na (b) K (c) Rb (d) Cs 14. Which of the following Carbonates does not yield CO 2 on heating ? (a) Li 2 CO 3 (b) Na 2 CO 3
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2 QUEST TUTORIALS Head Office : E-16/289, Sector-8, Rohini, New Delhi, Ph. 65395439 (c) MgCO 3 (d) CaCO 3 15. A solution of Na in liquid NH 3 serves a good reducing agent due to reaction (a) 2Na + 2NH 3 2NaNH 2 + H 2 (b) NaNH 2 + N 2 O NaN 3 + H 2 O (c) 2Na + 2N 2 O 2NaOH + H 2 (d) solvated electron 16. A neutral white solid (sodium salt) on heating liberates a gas and leaves an alkaline residue. The gas turn lime water milky. The solid is (a) Na 2 CO 3 (b) NaHSO 4 (c) NaHCO 3 (d) NaNH 4 HPO 4 17. A solid on heating gives a gas which supports combustion of Mg and P 4 is (a) NH 4 NO 2 (b) NaNO 3 (c) NH 4 NO 3 (d) Pb(NO 3 ) 2 18. In the solva process , the chief products are
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Unit14 s-block elements qns - 1 UNIT 14 IA AND IIA OR...

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