S – BLOCK ELEMENTS (ALKALI AND ALKALINE EARTH METALS) – 7

1) The solubility of the alkaline earth metal hydroxides increases from Be(OH)2 to Ba(OH)2 because
a) Hydration energy > Lattice energy
b) Lattice energy > Hydration energy
c) Hydration energy is equal to lattice energy
d) None is correct

2) MgBr2 and MgI2 are soluble in acetone because of
a) Their ionic nature
b) Their covalent nature
c) Their co-ordinate nature
d) None is correct

3) All alkali earth metal ions are
a) Coloured
b) Colourless
c) Paramagnetic
d) Colourless and diamagnetic

4) RRR Setting of plaster of Paris involves.
a) Hydration
b) Transition
c) Expansion
d) All are correct

5) The element found in plant systems which forms an important constituent in photosynthesis is
a) Fe
b) Cu
c) Na
d) Mg

6) The function of sand in mortar is
a) To decrease the hardness
b) To make the mass compact
c) To decrease the plasticity of the mass
d) To prevent excess shrinkage which may result in cracks

7) Which of the following solids has the highest lattice energy ?
a)
b)
c)
d)

8) The metal which does not dissolve in liquid ammonia is
a) Calcium
b) Sodium
c) Beryllium
d) Potassium

9) In smoke screens, calcium phosphide is used because it
a) Catches fire easily
b) Burns and gives and soot
c) Decomposes thermally
d) Forms phosphine which gives smoke

10) Ca, Sr and Ba generally form ionic compounds because of
a) Their high lattice energies
b) Low lattice energies
c) Their covalent nature
d) Their high ionisation energies

11) Ca, Sr and Ba dissolve in liquid ammonia giving a … solution
a) Highly conducting
b) Highly reducing
c) Paramagnetic
d) All are correct

12) The rate of setting of cement can be increased by
a) NaCl
b) KCl
c)
d)

13) Cement sets better with water and hardens well on dampening because the material that gives hardness to cement consists of
a) Limestone
b) Stable salts
c) Hydrated salts
d) Water absorbing stones

14) The melting point is highest for
a) Be
b) Mg
c) Sr
d) Ca

15) Which compound gives a basic and acidic oxide simultaneously on thermal decomposition?
a)
b)
c)
d)

16) The alkaline earth metal oxide having the co-ordination number 4 is
a) MgO
b) BeO
c) SrO
d) CaO

17) BeF2 is soluble in water whereas the fluorides of other alkaline earth metals are insoluble because of the
a)
b)
c)
d) None

18) Hardening of cement is due to
a) Hydrolysis
b) Polymerisation
c) Dehydration
d) Hydration and hydrolysis

19) The low solubility of BaSO4 in water is due to the
a)
b)
c)
d) None

20) When zeolite (hydrated sodium aluminium silicate) is treated with hard water, the Na+ ions are exchanged with
a)
b)
c)
d) None

21) Disodium hydrogen phosphate in the presence of NH4Cl and NH4OH gives a precipitate with a solution of Mg2+ ions. The precipitate is
a)
b)
c)
d)

22) Gypsum on heating at 120-1300C gives a
a) Hemihydrate
b) Monohydrate
c) Dihydrate
d) Anhydrous salt

23) A salt used as a purgative is
a) NaCl
b)
c)
d)

24) The main constituent of egg shells is
a)
b)
c)
d)

25) The compound soluble in acetic acid is
a) CaO
b)
c)
d)

26) When hydrated MgCl2.6H2O is strongly heated
a) MgO is formed
b)
c) Mg(OH)Cl is formed
d)

27) BaSO4 on fusion with Na2CO3 gives
a) BaO
b)
c)
d)

28) The cation which forms a yellow precipitate with potassium chromate in acetic acid is
a)
b)
c)
d)

29) Chemical A is used for water softening to remove temporary hardness. A reacts with sodium carbonate to generate caustic soda. When CO2 is bubbled through A, it turns cloudy. What is A ?
a)
b) CaO
c)
d)

30) To a clear solution of compound X, a solution of BaCl2 is added and a heavy white precipitate is formed which does not dissolve in dilute HCl. X is
a) Nitrate
b) Bromide
c) Sulphate
d) carbonate

31) In the alkaline earth metals, the electrons are more firmly held to the nucleus and hence the
a) Atoms of alkaline earth metals are bigger than alkali metals
b) lonisation energy of alkaline earths is greater than alkali metals
c) Reactivity of alkaline earths is greater than alkali metals
d) Alkaline earths are less abundant in nature

32) The basic character of the oxides MgO, SrO, K2O, NiO and Cs2O increases in the order
a)
b)
c)
d)

33) Calcium metal is used to produce high vacuum because it
a) Can remove water
b)
c) Is a good reducing agent
d) Is highly electropositive

34) Which of the following statements is not correct ?
a) Be like Al does not dissolve in alkalies
b) Oxides of both Be and Al are amphoteric
c)
d) Burning of limestone containing more than 10% aluminium silicate gives hydraulic mortar

35) Two metals X and Y form covalent halides. Both halides can act as Lewis acids and a catalyst in Friedel Crafts reaction. the halide of X is a polymer in the solid state and a dimer in the vapour state, and decomposes to a monomer at 1200 K. However, the halide of Y is a dimer in the vapour state and becomes ionic in the polar solvent. X and Y are respectively
a) Be, Al
b) Al, Be
c) Be, Ca
d) Mg, Ca

36) Mortar is a mixture of
a)
b) Slaked lime and water
c) Slaked lime, sand and water
d) None

37) Gypsum is added to clinker during cement manufacture to
a) Decrease the rate of setting of cement
b) Make the cement impervious
c) Bind the particles of calcium silicate
d) To facilitate the formation of colloidal gel

38) Portland cement is.
a) Calcium alumino silicate
b) Calcium aluminate + calcium silicate
c) A mixture of calcium oxide and silica
d) Calcium silicate + gypsum

39) Portland cement does not contain
a)
b)
c)
d)

40) Superphosphate of lime is a mixture of
a) Primary calcium phosphate and epsom salt
b) Primary magnesium phosphate and epsom salt
c) Primary magnesium phosphate and gypsum
d) Primary calcium phosphate and gypsum

41) Duraluminium is an alloy which contains
a) Mg + Al
b) Mg + Cu
c) Cu + Al
d) Mg + Cu + Al + Mn

42) RRR The blue coloured mineral Lapis Lazuli which is used as a semiprecious stone is a mineral of
a) Sodium alumino silicate
b) Zinc cobaltate
c) Basic copper carbonate
d) Prussian blue

43) Which of the following statements about AlCl3 is not correct ?
a) It exists as a dimer
b) It is a covalent compound
c) It involves back bonding between Cl and Al
d) Its aqueous solution conducts electricity

44) Boron differs from the other members of group III because
a) It has much lesser radius
b) It is a non metal
c) It is covalent in its compounds
d)

45) A certain compound when burnt gives three oxides. The first turned lime water milky. The second turned anhydrous CuS04 blue and the third formed an aqueous solution of low pH. The elements present in the compound are
a) C, O and S
b) C, H and Ca
c) C, H and Na
d) C, H and S

46) Which gas is used in very low temperature thermometers?
a)
b) He
c)
d)

47) The helium nucleus contains
a) 4 Protons
b) 4 neutrons
c) 2 neutrons and 2 protons
d) 3 protons and 2 electrons

48) The two electrons in the helium atom
a) Occupy different shells
b) Have different spins
c) Have the same spins
d) Occupy different subshells of the same subshell

49) Welding of magnesium can be done in an atmosphere of
a)
b) He
c)
d) All

50) The mineral from which potassium permanganate is manufactured is
a)
b)
c)
d)

51) Which one of the following oxidizing agents is not used for the oxidation of potassium manganate to potassium permanganate?
a)
b)
c)
d)

52) The electrolysis of potassium manganate solution gives
a)
b)
c)
d)

53) Baeyers reagent is
a)
b)
c)
d)

54) Which one of the following is not oxidized by acidified KMnO4?
a) Sod. oxalate
b) Pot. iodide
c) Ferrous sulphate
d) Sodium sulphate

55) Plaster of Paris is
a) CaSO4. H2O
b) 
CaSO4
c) 
CaSO4 . 2 H2O
d) 
CaSO4 . 1/2 H2O

56) Calcium is obtained by the
a) Electrolysis of molten calcium chloride
b) Electrolysis of a solution of calcium chloride
c) Reduction of Ca Cl2 with carbon
d) All of the given

57) Nesslers reagent is
a) KHg I4
b) 
K2Hg I4 + NH4OH
c) 
K2HgI4
d) 
KHgI4 + NH4OH

58) Magnesia mixture solution is used to test
a) As3+
b) 
PO4 3-
c) None
d) 
AS3+ and PO4 3-

59) Glazing of clay articles is generally done by
a) NaCl
b) KNO3
c) 
K2SO4
d) 
K2CO3

60) Baeyer’s reagent is
a) KMnO4 + H2SO4
b) 
KMnO4 + KOH
c) 
K2 Cr2 O7 + HCl
d) 
H2 Cr2 O7 + KOH

61) Soda ash has the chemical formula
a) Na2CO3
b) 
Na HCO3
c) 
Na OH
d) 
Na2O

62) Setting of cement is an
a) Exothermic reaction
b) Endothermic reaction
c) Neither exothermic nor endothermic
d) None of the above

63) Potassium is kept in
a) Kerosene oil
b) Water
c) Ammonia
d) Alcohol

64) Anhydrite is a name given to
a) Ca SO4
b) 
Ca S
c) 
Ca3 ( PO4)2
d) 
None of these

65) Which oxide is amphoteric?
a) Li2O
b) 
BeO
c) 
Ca O
d) 
K2O


Answer :

Ans 1) a

Ans Desc 1)

Ans 2) b

Ans Desc 2) MgBr2 and MgI2 are covalent in nature.

Ans 3) d

Ans Desc 3) Colourless and diamagnetic, because of the absence of unpaired electrons. They all have a stable noble gas configuration.

Ans 4) d

Ans Desc 4)

Ans 5) d

Ans Desc 5) Mg is present in chlorophyll.

Ans 6) d

Ans Desc 6)

Ans 7) b

Ans Desc 7) Be(OH)2 is almost insoluble in water. Thus it has the highest lattice energy.

Ans 8) c

Ans Desc 8) Be does not dissolve in liquid ammonia.

Ans 9) d

Ans Desc 9) Calcium phosphide liberates PH3 which gives smoke.

Ans 10) a

Ans Desc 10) Due to their high lattice energies

Ans 11) d

Ans Desc 11) Ammonia solvated electrons are responsible for these properties.

Ans 12) a

Ans Desc 12) The rate of setting of cement can be increased by NaCl

Ans 13) c

Ans Desc 13)

Ans 14) a

Ans Desc 14) The order of m.p. is Mg < Ra < Ba < Sr < Ca < Be.

Ans 15) c

Ans Desc 15) CaCO3 ® CaO (basic) + CO2 (acidic)

Ans 16) b

Ans Desc 16) Because a Be atom has only 4 available orbitals in its valency shell (Be =

Ans 17) c

Ans Desc 17) An ionic compound is soluble in water if its hydration energy > lattice energy.

Ans 18) d

Ans Desc 18)

Ans 19) c

Ans Desc 19) An ionic compound is soluble in water if its hydration energy > lattice energy.

Ans 20) b

Ans Desc 20) Na2Z+ Ca2+® CaZ + 2Na+.

Ans 21) c

Ans Desc 21) Mg2+ ions are precipitated as MgNH4PO4 in VI group of qualitative analysis.

Ans 22) a

Ans Desc 22) CaSO4.2H2O® CaS04.1/2H2O or 2(CaSO4).H2O

Ans 23) b

Ans Desc 23) Epsom salt is used as purgative.

Ans 24) a

Ans Desc 24) Egg shells are made of CaCO3.

Ans 25) d

Ans Desc 25) CaC2O4 is insoluble in acetic acid.

Ans 26) a

Ans Desc 26)

MgCl2.6H2OMgCl2.2H2O

Ans 27) b

Ans Desc 27) BaSO4 + Na2CO3BaCO3+ Na2SO4

Ans 28) b

Ans Desc 28) BaCrO4, a yellow solid, is insoluble in CH3COOH.

Ans 29) c

Ans Desc 29) Ca(OH)2 + Ca(HCO3)2® 2CaCO3 + 2H2O Ca(OH)2 + CO2® CaCO3+ H2O

Ans 30) c

Ans Desc 30) BaSO4 is white precipitate insoluble in dilute HCl

Ans 31) b

Ans Desc 31) When the electrons are more firmly held to the nucleus, more energy (ionisation energy) is required to remove the electrons.

Ans 32) c

Ans Desc 32) Alkali metal oxides are more basic than alkaline earth metal oxides and the basic nature increases as we move down the group.

Ans 33) b

Ans Desc 33) Calcium reacts with both O2 and N2 to remove them and form both oxide and nitride.

Ans 34) a

Ans Desc 34) Be, like Al dissolves in alkali. Be + 2NaOH® Na2BeO2 + H2.

Ans 35) b

Ans Desc 35) Covalent halides are formed by Be and Al among the metals given. The halide of Al, ie, Al2Cl6 becomes ionic in a polar solvent. Hence Y is Al. The halide of Be is a polymer in the solid state. Thus X is Be.

Ans 36) c

Ans Desc 36)

Ans 37) a

Ans Desc 37) Gypsum decreases the rate of setting of cement.

Ans 38) b

Ans Desc 38) Cement is considered as a mixture of calcium silicate and calcium aluminate.

Ans 39) d

Ans Desc 39) Cement is considered as a mixture of calcium silicate and calcium aluminate.

Ans 40) d

Ans Desc 40) Ca3(PO4)2+ CaSO4.2H2O

Ans 41) d

Ans Desc 41) Duraluminium or duralumin is made of Mg, Cu, Al and Mn.

Ans 42) a

Ans Desc 42) Lapis Lazuli is a mineral of sodium aluminosilicate.

Ans 43) c

Ans Desc 43) A co-ordinate bond is formed by the donation of a lone pair of electrons by Cl to Al.

Ans 44) b

Ans Desc 44) It is non-metal.

Ans 45) d

Ans Desc 45) The compound contains C, H and S as the elements which on burning give CO2, H2O and SO2 as oxides respectively. First oxide (CO2) turns lime water milky,the second oxide (H2O) turns anhydrous (white) CuSO4 blue due to hydration and the third oxide (SO2) dissolves in H2O giving an acid (H2S03) which lowers the pH of the solution. C, H, S are the elements in the compound

Ans 46) b

Ans Desc 46) He gas is used in the production of low temperatures. It is used in very low temperature thermometers.

Ans 47) c

Ans Desc 47) The helium nucleus contains 2 protons and 4-2 = 2 neutrons.

Ans 48) b

Ans Desc 48) The two electrons in helium atom (1s2) have different spins.

Ans 49) b

Ans Desc 49) He is used for providing inert atmosphere in the welding of metals such as Mg, Al, Ti etc.

Ans 50) a

Ans Desc 50) KMnO4 is manufactured from the mineral pyrolusite, MnO2

Ans 51) d

Ans Desc 51) H2O2 is a weak oxidising agent and cannot oxidise a strong oxidising agent like K2MnO4

Ans 52) d

Ans Desc 52) The oxygen evolved at the anode converts manganate to permanganate

Ans 53) b

Ans Desc 53) The dilute alkaline solution of KMnO4 is called Baeyers reagent

Ans 54) d

Ans Desc 54) Sodium sulphate is not a reducing agent and is not oxidised by acidified KMnO4

Ans 55) d

Ans Desc 55)

Ans 56) b

Ans Desc 56)

Ans 57) a

Ans Desc 57)

Ans 58) d

Ans Desc 58)

Ans 59) a

Ans Desc 59)

Ans 60) b

Ans Desc 60)

Ans 61) a

Ans Desc 61)

Ans 62) a

Ans Desc 62)

Ans 63) a

Ans Desc 63)

Ans 64) a

Ans Desc 64)

Ans 65) b

Ans Desc 65)

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