Resultados de las mediciones de Ultrasonido en el 2018 selladora SIEBLER HM1E-500 para tabletas efervescentes

lightest metal known in whole of periodic table ?

(A) Aluminium (B) Tin (C) Lithium (D) Beryllium

2. Alkali metals in each period of the periodic table have— (A) Smallest atomic radii (B) Highest electronegativity (C) Highest melting point (D) Lowest ionization potential 3. The strongest metal-metal bond

exists in—

(A) Lithium (B) Sodium (C) Potassium (D) Caesium 4. Which of the following com-

pounds does not exist in the solid state ?

(A) Na₂CO₃ (B) NaHCO₃ (C) Li₂CO₃ (D) LiHCO₃ 5. Which of the following is the

lightest element ?

(A) Potassium (B) Sodium (C) Rubidium (D) Caesium 6. When metallic sodium is heated

in presence of sufficient oxygen, whichofthefollowingcompounds is mainly formed ?

(A) Na₂O (B) Na₂O₂ (C) NaO (D) NaO₂ 7. Whichofthefollowingcompounds

is better used as a source of oxy- gen in space capsules, sub- marinesandinbreathingmasks? (A) Na₂O₂ (B) K₂O

(C) Li₂O (D) KO₂

8. Whichofthe following hydrides of alkali metals possesses the highest enthalpy of formation ?

(A) LiH (B) NaH

(C) PbH (D) CsH

9. Which of the following ions has lowest ionic mobility in aqueous solution ?

(A) Cs+ _{(B) Rb}+

(C) K+ (D) Li+

10. The metal which acts as strongest reducing agent in aqueous solution, is—

(A) Lithium (B) Sodium (C) Potassium (D) Rubidium

11. Whichofthefollowingcompounds is the most deliquescent in nature ?

(A) LiCl (B) NaCl

(C) KCl (D) RbCl

12. Whichofthefollowingcompounds hashighestcovalent characters ?

(A) NaF (B) NaCl

(C) NaBr (D) NaI

13. A colourless salt imparts yellow colour to Bunsen flame and its aqueous solution does not changethecolouroflitmuspaper. The salt is—

(A) K₂CO₃ (B) Na₂CO₃ (C) NaCl (D) CH₃COONa 14. Whichofthefollowingcompounds

has highest electrovalent charac- ters ?

(A) LiCl (B) BeCl₂ (C) MgCl₂ (D) KCl

15. Whichofthefollowinghalideshas the highest lattice energy and highest stability ?

(A) LiF (B) LiCl

(C) LiBr (D) LiI

16. Which of the following ions has the highest conductivity ? (A) Li+ _{(B) Na}+

(C) K+ _{(D) Rb}+

17. Whichofthefollowinghalideshas the highest melting point ?

(A) NaF (B) NaCl

(C) NaBr (D) NaI

18. Ionic potential of Li+ _{is almost}

equal to that of— (A) Mg2+ _ion

(B) Rb+ ion (C) Cs+ _ion

(D) Both (B) and (C)

19. The heat of hydration of alkali metal ions decreases in order :

Li+ > Na+ > K+ > Rb+ Which metal will react with water at the highest rate ?

(A) Li (B) Na

(C) K (D) Rb

20. Which among the following compounds is paramagnetic in nature ? (A) K₂O₂ (B) BaO₂ (C) KO₂ (D) None of these

21. The ionization potentials of alkali- metals are in order

Cs < Rb < K < Na < Li but Li is the strongest reducing agent. The strongest reducing nature of Li is attributed to— (A) Small size and high ioniza-

tion energy

(B) Small size and high heat of hydration

(C) Small size and low heat of hydration

(D) None of these

22. Which of the following nuclear reactions gives francium ? (A) Alpha decay of actinium (B) Beta decay of actinium (C) Gamma decay of actinium (D) Alpha decay of uranium 23. Whichofthefollowingcompounds

is extensively used in explo- sives ?

(A) K₂SO₄ (B) Na₂SO₄ (C) KNO₃ (D) K₂CO₃ 24. Sodium metal can be stored in—

(A) Kerosene oil (B) Benzene (C) Toluene (D) All of these

25. Which of the following is the incorrect statement ?

(A) Lithium has highest ioniza- tion potential among alkali metals

(B) Lithium is the lightest metal known

(C) Lithium is the strongest reducing agent among alkali metals

(D) Lithium chloride is totally insoluble in water

26. A dilute solution of sodium metal in liquid ammonia is strongly reducing on account of— (A) Sodium amide (B) Solvated cation (C) Solvated electron (D) Both (B) and (C)

27. Which of the following sodium salts is used for performing bead test in qualitative analysis ? (A) Borax

(B) Microcosmic salt (C) Potash alum (D) Both (A) and (B)

28. Whichofthefollowingalkalimetal ions is the best conductor of electricity ?

(A) Li+ _{(B) Na}+

(C) K+ (D) Cs+

29. Which of the following ions has the biggest size in aqueous solu- tion ?

(A) Li+ _{(B) Na}+

(C) Rb+ _{(D) Cs}+

30. A ruby red compound of an alkali metal when reacts with water gives ammonia. The compound is—

(A) NaN₃ (B) LiNO₂ (C) Li₃N (D) LiN₃ 31. Which of the following will be

diamagnetic in nature ?

(A) A dilute solution of Na in liquid ammonia

(B) A concentrated solution of Na in liquid ammonia (C) Sodium metal (D) None of these

32. Anhydrous form of sodium carbo- nate is commercially known as— (A) Washing soda

(B) Salt soda (C) Pearl ash (D) Soda ash

33. Squashes are preserved by adding—

(A) Sodium sulphate (B) Sodium metabisulphite (C) Microcosmic salt (D) None of these

34. Dry powder fire extinguishers contain—

(A) Soda ash and sand (B) Baking soda and sand (C) Pearl ash and sand (D) Sand only

35. The reactivity of sodium with water is made used in—

(A) Drying alcohol (B) Drying ammonia (C) Drying benzene (D) None of these

36. Which of the following is the by- product during the manufacture of Na₂CO₃ by Solvay process ? (A) Lime stone

(B) Calcium chloride (C) Ammonia (D) Carbon dioxide

37. Which of the following properties of lithium is more similar to that of other alkali metals as com- pared to that of magnesium ? (A) Oxidation state

(B) Electronegativity (C) Solubility of hydroxide (D) All of these

38. In which of the following proper- ties lithium resembles more with magnesiumascompared to other alkali metals ?

(A) Direct reaction with atmos- pheric nitrogen

(B) Greater solubility of its bicar- bonate than carbonate (C) Absence of peroxide in the

product of reaction with excess oxygen

(D) All of these

39. Which of the following is the wrong statement regarding fran- cium (Fr) ?

(A) It has bcc type of lattice (B) Themainproductofcombus-

tion of Fr metal in air is FrO₂ (C) Melting point of Fr is highest

of all alkali metals

(D) MeltingpointofFrClislowest of all chlorides of other alkali metals

40. The compound Cs BrCl₂ con- tains—

(A) C_s3+ and Cl– and Br– ions (B) C_s+ and BrCl₂– ions (C) C_s2+ and 2 Cl– and Br₂ (D) None of these

41. Which is the correct statement of the following ?

(A) E°red of Li is more positive

than that of Rb

(B) E°_ox of Li is more negative than that of Rb

(C) Rb is the stronger reducing agent than lithium

(D) None of these

42. Whatisthepercentageof NaCl in sea water ?

(A) 10 per cent (B) 5 per cent (C) 3 per cent (D) 15 per cent

43. Molten sodium is used in nuclear reactors to—

(A) Absorb neutrons (B) Slow down the neutrons (C) Absorb the heat (D) Absorb radioisotopes 44. The fire caused by combustion of

alkali metals can be extinguished by—

(A) Water (B) Kerosene

(C) Carbon tetrachloride (D) None of these

45. Which of the following substan- cesisformed when CO is passed over solid NaOH heated at 200°C ?

(A) Sodium carbonate (B) Sodium bicarbonate (C) Sodium acetate (D) Sodium formate

46. In the disproportionation of chlo- rinewithNaOH,themainreaction products are—

(A) NaCl and NaClO₄ (B) NaCl and NaOCl (C) NaCl and NaClO₂ (D) None of these

47. When sodium chloride is dis- solved in water—

(A) Na+ _{ion is oxidised}

(B) Na+ ion is hydrolysed (C) Cl– _{ion is hydrolysed}

(D) Both Na+ _{and Cl}– _{ions are}

hydrated

48. Which of the following is the correct increasing order of solu- bility in water ?

(A) CaCO₃ < NaHCO₃ < KHCO₃ (B) KHCO₃ < NaHCO₃ < CaCO₃ (C) NaHCO₃ < KHCO₃ < CaCO₃ (D) CaCO₃ < KHCO₃ < NaHCO₃ 49. Soda is—

(A) NaHCO₃.Na₂CO₃ (B) NaOH

(C) Na₂CO₃.10 H₂O (D) Na₂CO₃

C.S.V.

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