NCERT Class 11 Chemistry Chapter 10 S Block Elements Multiple Choice Questions

NCERT Solutions For Class 11 Chemistry Chapter 10 S Block Elements Multiple Choice Questions

Question 1. NO₂ is not obtained on heating—

1. AgNO₃
2. KNO₃
3. Cu(NO₃)₂
4. Pb(NO₃)₂

Answer: 2. KNO₃

KNO₃ on heating decomposes to form potassium nitrite (KNO₂) and oxygen gas

Question 2. Which one of the following has the lowest ionization

1. ls²2s²2p⁶
2. ls²s²2p⁶3s¹
3. ls²2s²2p⁵
4. ls²2s²2p³

Answer: 2. ls²s²2p⁶3s¹

Since the electronic configuration ls²s²2p⁶3s¹ is that of an alkali metal, its ionization potential value is the lowest.

Question 3. Which of the following represents the composition of carnallite mineral—

1. K₃O-Al₂O₃.6SiO₂
2. KNO₃
3. K₂SO4.MgSO₄-MgCl₂-6H₂O
4. KCl-MgCl₂-6H₂O

Answer: 4. KCl-MgCl₂-6H₂O

Carnallite:  KCl-MgCl₂-6H₂O

Question 4. Chlorine gas reacts with red-hot calcium oxide to give—

1. Bleaching powder and dichlorine monoxide
2. Bleaching powder and water
3. Calcium chloride and chlorine dioxide
4. Calcium chloride and oxygen

Answer: 4. Calcium chloride and oxygen

2CaO + 2Cl₂ → 2CaCl₂ + O₂

Question 5. The decreasing order of the basic characters of K₂O, BaO, CaO, and MgO is

1. K₂O > BaO > CaO > MgO
2. K₂O > CaO > BaO > MgO
3. MgO > BaO > CaO > K₂O
4. MgO>CaO>BaO>K₂O

Answer:   4. MgO>CaO>BaO>K₂O

The oxides of alkali metals are highly basic. The basic character of the oxides of alkaline earth metals increases on moving down the group.

Question 6. Match the flame colors of the alkaline earth metal salts in the Bunsen burner.

Answer: 4. 1 -A, 2-B,3-C

1. 1 -A, 2-C,3-B
2. 1 -C, 2-A,3-B
3. 1 -B, 2-C,3-A
4. 1 -A, 2-B,3-C

Question 7. The correct order of solubility in water is

1. CaSO₄>BaSO₄>BeSO₄>MgSO₄>SrSO₄
2. BeSO₄ > MgSO₄> CaSO₄> SrSO₄ > BaSO₄
3. BaSO₄>SrSO₄>CaSO₄>MgSO₄>BeSO₄
4. BeSO₄> CaSO₄ > MgSO₄ > SrSO₄> BaSO₄

Answer: 2. BeSO₄ > MgSO₄> CaSO₄> SrSO₄ > BaSO₄

Question 8. When BaCl₂ is added to an aqueous solution, a white precipitate is obtained. The anion among CO^2-₃ SO^2-₃ and SO^2-₄ that was present in the solution can be

1. CO^2-₃ But any of the other two
2. SO^2-₃ But not any of the other two
3. SO^2-₄ But not any of the other two
4. Any of them

Answer: 4. Any of them

BaSO₃, BaCO_3, and BaSO₄ are insoluble in water, thus they are precipitated out in an aqueous solution.

Question 9. Which of the following is least thermally stable

1. MgCO₃
2. CaCO₃
3. SrCO₃
4. BeCO₃

Answer: 4. BeCO₃

Question 10. Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides

1. MgO < K₂O < Al₂O₃ < Na₂O
2. Na₂O<K₂O<MgO<Al₂O₃
3. K₂O<Na₂O<Al₂O₃<MgO
4. Al₂O₃ < MgO < Na₂O < K₂ O

Answer: 4.Al₂O₃ < MgO < Na₂O < K₂ O

The basicity of the metallic oxides increases with the increase in electronegativity values of the metals.

Question 11. Which of the following on thermal decomposition yields a basic as well as an acidic oxide

1. KClO
2. CaCO₃
3. NH₄NO₃
4. NaNO₃

Answer: 2.CaCO₃

CaCO₃ at high temperature decomposes to form CaO and CO₂

Question 12. Which one of the following alkaline earth metal sulfates has its hydration enthalpy greater than its lattice

1. BaSO₄
2. SrSO₄
3. CaSO₄
4. BeSO₄

Answer: 4. BeSO₄

The hydration enthalpy of BeSO₄ is greater than Its lattice energy because of the very small size of Be ²⁺

Question 13. The main oxides formed on combustion of, Na and Kin excess of air respectively are

1. LiO₂, Na₂O and KOH
2. LiO₂, Na₂O₂ and K₂O
3. Li₂O₂, Na₂O₂ and KO
4. Li₂O₂, Na₂O₂ and KO₂

Answer: 4. Li₂O₂, Na₂O₂ and KO₂

4Li + O₂ →2Li₂O

2Na + O→Na₂O₂

K + O→KO

Question 14. Although lithium and magnesium resemble each other in properties due to a diagonal relationship, the following statement is not correct

1. Both of them form a nitride compound
2. When nitrates of both Li and Mg are heated, NO₂ and O₂ are obtained
3. Both of them form basic carbonate salt
4. Both of them form soluble bicarbonate salt

Answer: 3. Both of them form basic carbonate salt

Magnesium forms basic bicarbonate salt [3MgCO₃.Mg(OH)₂ .3H₂O] whereas lithium forms carbonate salt [Li₂CO₃]. I cannot form any basic bicarbonates.

Question 15. Match Column – A Column – B for the compositions of substances and select the correct answer using the code given below

1. 1 -C, 2-D, 3-  A, 4- B
2. 1 -B, 2-C, 3-  D, 4- A
3. 1 -A, 2-B, 3-  C, 4- E
4. 1 -D, 2-C, 3-  A, 4- B

Answer: 2. 1 -B, 2-C, 3-  D, 4- A

Plaster of Paris: CaSO₄– ½H₂O

Epsomite: MgSO₄-7H₂O

Kieserite: MgSO₄-H₂O

Gypsum: CaSO₄-2H₂O

Question 16. Which one of the following is present as an active ingredient in bleaching powder for bleaching action

1. CaOCl₂
2. Ca(OCl)₂
3. CaO₂Cl
4. CaCl₂

Answer: 2.Ca(OCl)₂

Bleaching powder is – a mixture of calcium chlorohypochlorite [Ca(OCl)₂] and basic calcium chloride [CaCl₂-Ca(OH)₂-2H₂O]. The compound present as an active ingredient in bleaching powder for bleaching action is Ca(OCl)₂

Question 17. Which of the following has the lowest melting point

1. CaCl₂
2. CaBr₂
3. Cal₂
4. CaF₂

Answer: 3.Cal₂

With the increase in the size of the halogens (from toI), the covalent character of the corresponding compounds (from CaF₂ to Cal₂) increases. Therefore, the melting points of the compounds decrease.

Question 18. In the case of replacement reaction, the reaction will be most favorable if M happens to be

1. K
2. Rb
3. Li
4. Na

Answer: 2. Rb

For a particular alkyl halide, the reactivity of the alkali metal fluorides increases gradually from Li to Cs because their ionization enthalpies decrease and their electronegativities increase. Therefore, for the given reaction, if M = Rb, then the reaction becomes most favorable.

Question 19. Which one of the alkali metals forms only the normal oxide M₂O on heating in air

1. Li
2. Na
3. Rb
4. K

Answer: 1. Li

Question 20. The ease of adsorption of the hydrated alkali metal ions on the ion-exchange resins follows the order

1. K⁺ < Na+ ⁺ Rb⁺ < Li⁺
2. Na⁺ < Li⁺ < K⁺ < Rb⁺
3. Li⁺ < K⁺ < Na⁺ < Rb⁺
4. Rb⁺ < K+< Na+< Li⁺

Answer: 4. Li⁺ < K⁺ < Na⁺ < Rb⁺ 

The ease of adsorption of the hydrated alkali metal ions on the ion-exchange resins decreases with the increase in the size of the alkali metal. The correct order of the sizes of the alkali metals is Li⁺ < Na⁺ < K⁺ < Rb⁺ .4.

The ease of adsorption of the hydrated alkali metal ions on the ion-exchange resins decreases with the increase in the size of the alkali metal. The correct order of the sizes of the alkali metals is: Li⁺ < Na⁺ < K⁺ < Rb⁺

Question 21. Be²⁺is isoelectronic with which of the following ions

1. Na⁺
2. Mg²⁺
3. H⁺
4. Li⁺

Answer: 4. Li⁺

No. ofelectrons in Be = 4

.-. No. of electrons in Be²⁺ = 2

Again, no. of electrons in Li = 3

No. ofelectrons in Li+ = 2

Therefore, Be²⁺ is isoelectronic with Li⁺

Question 22. On heating which of the following releases CO₂ most easily

1. K₂CO₃
2. Na₂CO₃
3. MgCO₃
4. CaCO₃

Answer: 3.

The thermal stability of the given compounds follows the order: of K₂CO₃ > Na₂CO₂ > CaCO₂ > MgCO₂.

Thus, MgCO₃ Can release CO₂ most easily on heating.

Question 23. In contrast with beryllium, which one of the following statements is incorrect

1. It forms Be₂C
2. Its salts rarely hydrolyzed
3. Its hydride is electron deficient and polymeric
4. It is rendered passive by nitric acid

Answer: 2. Its salts rarely hydrolyzed

Beryllium forms covalent compounds, thus hydrolysis of beryllium compounds occurs readily.

Question 24. The suspension of slaked lime in water is

1. Quicklime
2. Milk of lime
3. Aqueous solution of slaked lime
4. Lime water

Answer: 2. Milk of lime

Suspension of slaked lime Is known as ‘milk ofIimei

Question 25. Which of the following statements is false

1. Mg ²⁺ ions form a complex with ATP
2. Ca²⁺ ions are important in blood clotting
3. Ca²⁺ ions are not important in maintaining the regular beating of the heart
4. Mg²⁺ ions are important in the green parts of plants

Answer: 3. Ca²⁺ ions are not important in maintaining the regular beating of the heart

Ca²⁺ plays an important role in the regular beating of the heart

Question 26. The product obtained as a result of a reaction of nitrogen

1. Ca(CN)₂
2. CaCN₃
3. Ca₂CN
4. CaCN

Answer: The given options are not correct

Question 27. Which one of the following takes up CO₂ and releases

1. K₂O
2. CaO
3. KO₂
4. KOH

Answer: 3.KO₂

2KO₂ + CO₂ → K₂ CO₃ + \(\frac{3}{2}\) O₂

Question 28. Ionic mobility of which of the following alkali metal ions is lowest when the aqueous solution of these salts is put under an electric field

1. K
2. Rb
3. Li
4. Na

Answer: 3. Li

Question 29. Magnesium reacts with an element (X) to form an ionic compound. If the ground state electronic configuration of (X) is ls²2s²2p³ the simplest formula for this compound is

1. Mg₃X₂
2. Mg₂X₃
3. Mg₂X
4. Mg X₂

Answer: 1. Mg₃X₂

Electronic configuration of X: ls²2s²2p³

Valency of X = 3

Here, the valency of Mg = 2

Thus the compound will be Mg₃X₂

Question 30. Which of the following oxides is the most acidic in nature

1. CaO
2. MgO
3. BaO
4. BeO

Answer: 4. BeO

On moving down the group basic character of the gr-2 On moving down the group basic character of the gr-2

BeO < MgO < CaO < SrO < BaO

Thus, BeO is acidic among all the given oxides.

Question 31. Among CaH₂, BeH₂, BaH₂ the order of ionic character

1. BaH₂< BeH₂ < CaH₂
2. BeH₂ < CaH₂ < BaH₂
3. BeH₂<BaH₂<CaH₂
4.  CaH₂ < BeH₂, < BaH₂

Answer: 2.BeH₂ < CaH₂ < BaH₂

Question 32. Which of the following is not hygroscopic

1. CsCl
2. MgCl₂
3. CaCl₂
4. LiCI

Answer: 1. CsCl is not hygroscopic while MgCl,  CaCI_4, and LiCl are hygroscopic

Question 33. Which is the correct order of solubility in water—

1. Ba(OH)₂ <Mg(OH)₂
2. BaCO₃ >CaCO₃
3. CaSO₄ <MgSO₄
4. Ca(OH)2^Mg(OH)₂

Answer: 3. CaSO₄ <MgSO₄

Question 34. Bleaching powder does not contain—

1. CaCl₂
2. Ca(OH)₂
3. Ca(OCl)₂
4. Ca(ClO₃ )₂

Answer: 4.Ca(ClO₃)₂

Bleaching powder is a mixture of calcium hypochlorite, Ca(OCI)_2, and the basic chloride CaCl₂, H₂O with some slaked lime, Ca(OH)₂.

Question 35. Which of the following statements is incorrect—

1. Li⁺ has a minimum degree of hydration
2. The oxidation state of K in KO₂ is +1
3. Na is used to make a Na/Pb alloy
4. MgSO₄ is readily soluble in water

Answer: 1.  Li⁺ has a minimum degree of hydration

The hydration enthalpies of alkali metal ions decrease with an increase in ionic sizes. Hence, the orderis Li⁺ > Na⁺ > K⁺ > Rb⁺ > Cs⁺. Therefore Li⁺ has a maximum degree of hydration

Question 36. Which of the following has the highest hydration energy

1. MgCl₂
2. CaCl₂
3. BaCl₂
4. SrCl₂

Answer: 1. MgCl₂

Smaller-sized and highly charged metal ions have higher hydration energy. Therefore, the order of hydration energy will be

Be²⁺ > Mg²⁺ > Ca²⁺ > Sr²⁺ > Ba²⁺

Question 37. Which is the correct order of solubility in water

1. Ba(OH)₂< Mg(OH)₂
2. BaCO₃ >CaCO₃
3. CaSO₄ < MgSO₄
4. Ca(OH)₂ ≅ Mg(OH)₂

Answer: 3.CaSO₄ < MgSO₄

Question 38. What is the product of the reaction between the dilute solution of Ba(OH)₂ and H₂O₂ + ClO₂ 

1. HOCl
2. Ba(OCl)₂
3. Ba(ClO₃)₂
4. Ba(ClO₂)₂

Answer: 4.Ba(ClO₂)₂ 

Ba(OH)₂  +H₂ O₂  + 2ClO₂  → Ba(ClO₂ )₂  + 2H₂ O + O₂ 

Question 39. Which of the following compounds transforms baking soda into baking powder

1. KHCO₃
2. NaHCO₃
3. KHC₄H₄O₆
4. KCl

Answer: 3.KHC₄H₄O₃

Question 40. Which of the following pair of compounds does not undergo any chemical change on heating

1. MgCO₃,KHCO₃
2. CS₂CO₃,KNO₂
3. Na₂CO₃,NaNO₃
4. Li₂CO₃, KNO₂

Answer: 2.  CS₂CO₃, KNO₂

Question 41. Ca(OH)₂ (anhydrous)  CaCl₂ +B In this reaction, B is

1. CaOCl₂
2. Ca(ClO₃)₂
3. Ca(OH)₂
4. Ca(ClO₂)₂

Answer: 2. Ca(ClO₃)₂

Question 42. The blue color of potassium solution in liquid ammonia is due to the presence of

1. Solvated electron
2. Potassium amide
3. Impurities present in potassium
4. Potassium oxide

Answer: 1. Solvated electron

Question 43. The alkali metal that does not participate in the reaction MI + I₂ → MI₃ is

1. Na
2. K
3. Rb
4. Cs

Answer: 1. Na

Question 44. The lithium compound which is soluble in water is

1. Li₂CO₃
2. LiNO₃
3. LiF
4. Li₃PO₄

Answer: 2. LiNO₃

Question 45. An alkaline earth metal when heated along with nitrogen forms X. On hydrolysis, X forms an insoluble basic compound and a gas which turns CuSO₄ solution deep blue. The metal is

1. Be
2. Ca
3. Mg
4. Ba

Answer: 3. Mg

Question 46. Which of the following compounds exists in only an aqueous solution

1. Li₃PO₄
2. NaHCO₃
3. [Li(NH₃)₄]I
4. LiHCO₃

Answer: 4.LiHCO₃

Question 47. Which of the following acids does not liberate CO₂ on reacting with sodium carbonate

1. Dilute HCl
2. Dilute H₃BO₃
3. Dilute H₃PO₄
4. Dilute H₂PO₄

Answer: 2. Dilute H₃BO₃

Question 48. Hydrated BeCl₂ acts as a/an

1. Lewis base
2. Arrhenius base
3. Arrhenius acid
4. Lewis acid

Answer: 4. Lewis acid

Question 49. Which of the following compounds or pair of compounds is responsible for turning yellow sodium peroxide white in the presence of air

1. Na
2. NaOH and Na₂CO
3. H₂O₂
4. NaOH and H₂O₂

Answer: 2.NaOH and Na₂CO

Question 50. The chemical formula ofmicrocosmic saltis

1. NaHPO₄.2H₂O
2. NH₄₃HPO₄.2H₂O
3. Na(NH₄)HPO₄.4H₂O
4. (NH₄)3HPO₄.4H₂O

Answer: 3.Na(NH₄)HPO₄.4H₂O

Question 51. The hydride which does not form as a result of a direct reaction between the metal and hydrogen is

1. CaH₂
2. MgH₂
3. BeH₂
4. NaH

Answer: 3.BeH₂

Question 52. An amphoteric oxide dissolves in HCl to form a salt. The salt does not impart any characteristic color to the flame but fumes in moist air. The oxide is

1. BaO₂
2. MgO
3. BeO
4. CaO

Answer: 3. BeO

Question 53. The difference in the number of water molecules in gypsum and Plaster of Paris is—

1. 5/2
2. 2
3. 1/2
4. 3/2

Answer: 4. 3/2

Question 54. Compound A imparts a brick-red color to the flame and decomposes on heating to produce oxygen and a brown gas. A is

1. Mg(NO₃)₂
2. Ba(NO₃)2
3. Ca(NO₃)₂
4. Sr(NO₃)₂

Answer: 2. Ba(NO₃)₂

Question 55. The sodium salt of an unknown anion when heated with MgCl₂ forms a white precipitate. The anion is

1. SO^2-₄
2. CO^2-₃
3. HCO^–₃
4. NO^–₃

Answer: 3.HCO^–₃

Question 56. The salt which is added to table salt to keep it dry and free-flowing

1. KCl
2. Ca(PO₄)₂
3. KI
4. Na₃PO₄

Answer: 2.Ca(PO₄)₂

Question 57. The compound which acts as an oxidizing as well as a reducing agent

1. NaNO₃
2. Na₂O
3. Na₂O₂
4. KNO₃

Answer: 3.

Question 58. The compound which is used to extinguish fire caused by combustion of alkali metals is—

1. CC1₄
2. Sand
3. Water
4. Kerosene

Answer: 1.  CC1₄

Question 59. An aqueous solution of sodium sulfate is electrolyzed using inert electrodes. The products formed at the cathode and anode respectively are

1. O₂,H₂
2. H₂,O₂
3. O₂, Na
4. O₂,SO₂

Answer: 1.O₂, H₂

Question 60. Sodium when heated at 300°C in air forms X which absorbs CO₂ to form Na₂CO₃ and a compound Y. The compound Y is 

1. H₂
2. O₂
3. H₂O₂
4. O₃

Answer: 2.O₂

Question 61. Excess Na⁺ ions in the human body cause

1. Diabetes
2. Anaemia
3. Low blood pressure
4. High blood pressure

Answer: 4. High blood pressure

Question 62. The metal carbide which on hydrolysis produces allylene or propyne is

1. Be
2. Ca
3. Al
4. Mg

Answer: 4. Mg

Question 63. A metal M readily forms water-soluble sulfate MSO₄, water-insoluble hydroxide M(OH)_2, and oxide MO. The oxide remains inert on heating. The hydroxide is soluble in NaOH. M is

1. Be
2. Mg
3. Ca
4. Sr

Answer: 1. Be

Question 64. When compound A is heated, it produces a colorless gas, and the residue obtained is dissolved in water to form compound B. The compound C is formed when excess CO₂ is passed through the aqueous solution of B. The compound C can be separated in a solid state from its solution. C in its solid state when heated forms the compound A. Ais

1. CaCO₃
2. Na₂CO₃
3. K₂CO₃
4. CaSO₄.2H₂O

Answer: 1.CaCO₃

Question 65. When metals A and B are heated in air, A only forms oxide but B forms both oxide and nitride. A and B are

1. Cs, K
2. Mg, Ca
3. Li, Na
4. K, Mg

Answer: 4. K, Mg

Question 66. The alkali metal which emits a light of the longest wavelength in the flame testis

1. Na
2. K
3. Cs
4. Li

Answer: 2. K

Question 67. The compound which does not form a double salt is

1. Li₂SO₄
2. Na₂SO₄
3. K₂SO₄
4. Rb₂SO₄

Answer: 1. Li₂SO₄

Question 68. The decreasing order of stability of the chloride salts of alkali metals is

1. LiCl > KCl > NaCl > CsCl
2. CsCl > KCl > NaCl > LiCl
3. NaCl > KCl > LiCl > CsCl
4. KCl > CsCl > NaCl > LiCl

Answer: 4. KCl > CsCl > NaCl > LiCl

Question 69. The affinity of sodium for water is used for drying

1. Alcohol
2. Ammonia
3. Benzene
4. Phenol

Answer: 3. Benzene

Question 70. The ions present in an anhydrous mixture of potassium fluoride and hydrofluoric acid are

1. K⁺,H⁺ F^–
2. (KF)⁺+ (HF)^–
3. KH⁺, F^–
4. K⁺,HF₂^–

Answer: 4. K⁺,HF₂^–

Question 71. The correct order of covalent character in the following compounds is

1. LiCl < NaCl < BeCl₂
2. BeCl₂ > LiCl > NaCl
3. NaCl < LiCl < BeCl₂
4. BeCl₂ < NaCl < LiCl

Answer: 3. NaCl < LiCl < BeCl₂

Question 72. A chemical compound A is used for the recovery of ammonia during the preparation of washing soda. When CO₂ is passed through the aqueous solution of A, the solution turns turbid. A is used for whitewashing because of its disinfecting properties. The chemical formula of A is

1. Ca(HCO₃)₂
2. CaO
3. Ca(OH)₂
4. CaCO₃

Answer: 3. Ca(OH)₂

Question 73. The compound used for drying neutral or basic gases is—

1. Calcium carbonate
2. Sodium carbonate
3. Sodium bicarbonate
4. Calcium oxide

Answer: 4. Calcium oxide

Question 74. Which of the following compounds does not contain calcium carbonate

1. Dolomite
2. Marble statue
3. Burnt gypsum
4. Snail shell

Answer: 3. Burnt gypsum

Question 75. The compound which on thermal decomposition produces a basic and an acidic oxide is

1. KClO₃
2. Na₂CO₃
3. NaNO₃
4. CaCO₃

Answer: 4.CaCO₃

Question 76. Which of the following oxides does not react with water

1. BeO
2. CaO
3. MgO
4. SrO

Answer: 1. BeO

Question 77. Which of the following carbonates is soluble in water

1. SrCO₃
2. BaCO₃
3. Al₂(CO₃)₃
4. Rb₃CO₃

Answer: 3.Al₂(CO₃)₃

Question 78. The compound whose aqueous solution is called ‘baryta water’ is

1. BaSO₄
2. BaO
3. BaCO₃
4. Ba(OH)₂

Answer: 4. Ba(OH)₂

Question 79. The alkali metal that emits a light of the shortest wavelength in the flame test is

1. Na
2. K
3. Cs
4. Li

Answer: 3. Cs

Question 80. The correct order of ionic mobility of the following ions in their aqueous solution is

1. Na⁺> K⁺> Rb⁺> Cs⁺
2. K⁺> Na⁺ > Rb⁺> Cs⁺
3. Cs⁺ > Rb⁺ > K⁺ > Na⁺
4. Rb⁺ > K⁺ > Cs⁺ > Na⁺

Answer: 3. Cs⁺ > Rb⁺ > K⁺ > Na⁺

Question 81. Which of the following compounds is not used for storing or immersing metallic sodium

1. Benzene
2. Kerosene
3. Ethanol
4. Toluene

Answer: 3. Ethanol

Question 82. Which of the following compounds is paramagnetic

1. KO₂
2. SiO₂
3. TiO₂
4. BaO₂

Answer: 1.KO₂

Question 83. KO₂ is used in oxygen cylinders that are used for submarines and spacecraft because—

1. It increases the amount of oxygen by absorbing CO₂
2. It eliminates water vapor
3. It absorbs CO₂
4. It forms O₃

Answer: 1. It increases the amount of oxygen by absorbing CO₂

Question 84. Which of the following compounds is the most stable

1. LiF
2. LiCl
3. LiBr
4. Lil

Answer: 1. LiF

Question 85. The alkali metal for which the photoelectric effect is maximum is

1. Cs
2. Na
3. K
4. Li

Answer: 1. Cs

Question 86. The melting points of alkali metals are low. Which of the alkali metals melts when room temperature becomes more than 30 °C 

1. K
2. Na
3. Cs
4. Rb

Answer: 3. Cs

Question 87. Which of the following alkali metal hydroxides is the most basic

1. CsOH
2. KOH
3. Li OH
4. RbOH

Answer: 1.CsOH

Question 88. The metal whose carbonate salt is the most stable is

1. Na
2. Mg
3. A1
4. Si

Answer: 1. Na

Question 89. Which of the following compounds is used for manufacturing soft soaps

1. KOH
2. NaOH
3. LiOH
4. Mg(OH)₂

Answer: 1.

Question 90. The atomic number of a radioactive alkali metal is

1. 55
2. 87
3. 19
4. 37

Answer: 2. 87

Question 91. Which of the following is used for the manufacture of high? temperature thermometers

1. An alloy of Li and Na
2. An alloy of Na and Cs
3. An alloy of Na and K
4. An alloy of K and Rb

Answer: 3. An alloy of Na and K

Question 92. The mixture of MgCl₂ and MgO is known as

1. Sorel’s cement
2. Portland cement
3. Alum
4. Magnesium oxychloride

Answer: 1. Sorel’s cement

Question 93. Which of the following alkaline earth metals does not form its corresponding hydride by directly reacting with hydrogen

1. Mg
2. Sr
3. Be
4. Ba

Answer: 3. Be

Question 94. Which of the following alkaline earth metal hydroxides is soluble in NaOH solution

1. Ba(OH)₂
2. Ca(OH)₂
3. Mg(OH)₂
4. Be(OH)₂

Answer: 4. Be(OH)₂

Question 95. The chloride salt which is soluble in ethanol is

1. BeCl₂
2. CaCl₂
3. SrCl₂
4. MgCl₂

Answer: 1.BeCl₂

Question 96. Which of the following is produced when one mole of magnesium nitride reacts with an excess of water

1. One mole of ammonia
2. One mole of nitric acid
3. Two moles of ammonia
4. Two moles of nitric acid

Answer: 3. Two moles of ammonia

Question 97. Which of the following methods is used for the preparation of calcium

1. Reduction of CaO by carbon
2. Reduction of CaO by hydrogen
3. Electrolysis of a mixture of anhydrous CaCl₂ and KCl
4. Electrolysis of molten Ca(OH)₂

Answer: 3. Electrolysis of a mixture of anhydrous CaCl₂ and KCl

Question 98. Which alkaline earth metal ion plays a vital role in the contraction of muscles

1. Ba²⁺
2. Sr²⁺
3. Mg²⁺
4. Ca²⁺

Answer: 4. Ca²⁺

Question 99. Which of the following correctly indicates the formula of halides of alkaline earth metals

1. BeCl₂.2H₂O
2. BeCl₂.4H₂O
3. CaCl₂.6H₂O
4. SrCl₂.4H₂O

Answer: 1.BeCl₂.2H₂O

Question 100. The compounds of sodium which are used in the textile Industry are

1. Na₂CO₃
2. NaHCO₃
3. NaOH
4. NaCl

Answer: 1. Na₂CO₃

Question 101. Which of die following pairs of elements have similar properties

1. Be, Cs
2. K, Cs
3. Sr, Rb
4. Be, Al

Answer: 2. K, Cs

Question 102. The chlorides which are soluble in pyridine are

1. LiCl
2. CsCl
3. NaCl
4. BeCl₂

Answer: 1 and 4

Question 103. The gases in which magnesium burns are

1. CO₂
2. N₂O
3. N₂
4. SO₂

Answer: 1,2,3 and 4

Question 104. Which of the following oxides have rock salt structure with coordination number 6:6 

1. MgO
2. CaO
3. SrO
4. B₂O₃

Answer: 1,2 and 3

Question 105. Which of the following pairs of compounds cannot exist in aqueous solution

1. NaH₂PO₄ and Na₂HCO₃
2. Na₂CO₃ and NaHCO₃
3. NaOH and NaH₂ PO₄
4. NaHCO₃ and NaOH

Answer: 3 and 4

Question 106. The compounds which on heating do not form oxides are

1. NaNO₃
2. CsOH
3. LiOH
4. SrCO₃

Answer: 1 and 2

Question 107. Which of the following pairs of elements will give superoxides and peroxides respectively when heated with excess air

1. K, Br
2. Nay Rb
3. K, Rb d
4. Na, Ba

Answer: 3 and 4

Question 108. Which of the following do not respond to flame test

1. Be
2. Mg
3. KO₂
4. Sr

Answer: 1 and 2

Question 109. Which of the following compounds are not paramagnetic in nature

1. K₂O₂
2. NO₂
3. KO₂
4. K₂O

Answer: 1 and 4

Question 110. Which of the following is incorrect

1. Soda ash: Na₂CO₃
2. Pearl ash: Cu₂CO₃
3. Bone ash: K₂CO₃
4. Baking soda: NaHCO₃

Answer: 2 and 3

Question 111. Which ions of water are replaced by sodium ions when hard water is passed through zeolite (hydrated sodium aluminum silicate)

1. H⁺
2. Mg⁺
3. Ca²⁺
4. SOl₄^2-

Answer: 2 and 3

Question 112. The compounds which are soluble in organic solvents are

1. CaCl₂
2. BaCl₂
3. BeCl₂
4. AlCl₃

Answer: 3 and 4

Question 113. The compounds formed when potassium superoxide reacts with water are

1. KOH
2. H₂O₂
3. K₂O₂
4. O₂

Answer: 1, 2 and 4

Question 114. Which of the following hydrated salts undergo hydrolysis on heating

1. BaCl₂.2H₂O
2. MgCl₂.6H₂O
3. SrCl₂.2H₂O
4. CaCl₂.6H₂O

Answer: 2 and 4

Question 115. Which of the following compounds are extensively used as drying agents

1. Anhydrous CaCl₂
2. Mg(ClO₄)2
3. BeC
4. Ca(OH)₂

Answer: 1 and 2

Question 116. Each of the following compounds reacts with water but which of these liberates the same gas

1. Na
2. Na₂O₂
3. KO₂
4. NaH

Answer: 1 and 4

Question 117. The polarisability of LiCl is higher than that of NaCl. Concerning this, which of the following statements is true

1. The melting point of LiCl is less than that of NaCl
2. LiCl is sparingly soluble in organic solvents
3. LiCl dissociates to a greater extent in water than NaCl
4. The conductivity of molten LiCl is less than that of NaCl

Answer: 1 and 4

Question 118. Which of the following statements is correct

1. Electronegativity of alkali metals decreases with an increase in atomic number
2. Lithium is the lightest metal
3. Alkali metals are strong reducing agents –
4. The electronegativity of alkali metals ranges from 1.0 to 0.7

Answer: 1, 3, 4

Question 119. Which of the following statements are incorrect about the hydrates of alkali metals

1. Conduct electricity in their molten states
2. These compounds act as oxidizing agents
3. These compounds dissolve in water to liberate
4. These compounds are covalent

Answer: 2 and 4

Question 120. Which of the following statements are correct about the ionic solids KI and CaO lattice enthalpy of CaO is greater than that of K₃

1. I am soluble in benzene
2. The melting point of CaO is high
3. The melting point of KI is high

Answer: 1, 2, 3

Question 121. The compounds which do not form NO₂ on undergoing thermal decomposition are

1. LiNO₃
2. NaNO₃
3. KNO₃
4. RbNO₃

Answer: 2, 3, and 4

Question 122. Metals are identified by their standard reduction potential, enthalpy of fusion, and atomic size. The alkali metals are identified by their

1. High boiling point
2. High negative standard reduction potential
3. High density
4. Greater atomic size

Answer: 2 and 4

Question 123. Which of the following sulfates easily dissolve in water

1. BeSO₄
2. MgSO₄
3. BaSO₄
4. SrSO₄

Answer: 1 and 2

Question 124. The properties of beryllium nitride which are different from the nitrides of other alkaline earth metals are

1. Its volatility
2. Its covalent nature
3. Unable to undergo hydrolysis
4. Its ionic nature

Answer: 1 and 2

Question 125. Which of the following options is correct for RbO₂

1. It is a peroxide
2. It is diamagnetic
3. It is a superoxide
4. It is paramagnetic

Answer: 3 and 4

Question 126. Which of the following statements is correct for the alkaline earth metals

1. Hydration enthalpy of Sr²⁺is less than that of Ba²⁺
2. CaCO₄ undergoes decomposition at a higher temperature than BaCO₃
3. Ba(OH)₂ is a stronger base than Mg(OH)₂
4. SrSO₄  is more soluble in water than CaSO₄

Answer: 2 and 3

Question 127.  Which of the following statements are correct about the alloy formed by sodium and potassium

1. It is used in Lassaigne’s test
2. It is liquid at ordinary temperature
3. It is used in specially designed thermometers
4. It is used as a coolant in nuclear reactors

Answer: 2 and 3

Question 128. Which of the following statements is incorrect

1. BeCl₂ molecule is linear in the gaseous state
2. Calcium hydride is known as hydrolith
3. Carbides of both beryllium and calcium react with water to form acetylene
4. Oxides of both Be and Ca are amphoteric

Answer: 3 and 4

Question 129. Which of the following is less stable thermally

1. LiF
2. KCl
3. RbF
4. CsF

Answer: 2. KCl

The thermal stability of a compound increases with the increasing value of enthalpy of formation. Among the given compounds the value of enthalpy of formation is minimum (-428kJ.mol^-1) for KCl. Hence, it has the lowest thermal stability among the given compounds.

Question 130. Which of the following pairs is responsible for developing an electric potential across the membrane of living cells

1. Ca²⁺and Na⁺
2. Na⁺ and K⁺
3. K⁺ and Ba²⁺
4. Mg²⁺ and Ca²⁺

Answer: 3. K⁺ and Ba²⁺

Question 131. Which one of the following chlorides is a soluble organic solvent

1. CaCl₂
2. NaCl
3. MgCl
4. BeCl₂

Answer: 4.MgCl

Question 132. Which of the following alkaline earth metal carbonates is thermally least stable

1. BaCO₃
2. CaCO₃
3. SrCO₃
4. BeCO₃

Answer: 4.SrCO₃

Question 133. The cause of the different colors of the flame in the flame test is

1. Lowionisation potential
2. Low melting point
3. Malleability
4. The presence of one electron in the outermost orbit

Answer: 1. Lowionisation potential

Question 134. Which of the following alkaline earth metal sulfate is most soluble in water

1. CaSO₄
2. SrSO₄
3. BaSO₄
4. MgSO₄

Answer: 4. BaSO₄

Question 135. What will be the order of reducing powder of the following elements Li, Na,  K, Rb, Cs

1. Cs > Rb > K > Na > Li
2. Rb > Cs > K > Na > Li
3. K > Rb > Cs > Na > Li
4. Na > Li> K >Cs > Rb

Answer: 1. Cs > Rb > K > Na > Li

The order of reducing free states is:

Cs > Rb > K > Na > Li

Question 136. Which one of the following elements shows a diagonal relationship with magnesium

1. Na
2. Li
3. Be
4. Ca

Answer: 2. Li

Question 137. Sodium is preserved in which of the following liquids

1. Water
2. Ethanol
3. Kerosene oil
4. Methanol

Answer: 3. Kerosene oil

Question 138. Which of the alkali metals has having least melting point?

1. Na
2. K
3. Rb
4. Cs

Answer:  4. Cs

As the atomic size of the metal increases, the strength of metallic bonding decreases and consequently, the melting point decreases. Since the size of the cesium atom is the largest, it has the least melting point.

Question 139. Which one of the following alkali metals gives hydrated salts? 

1. Li
2. Na
3. K
4. Cs

Answer: 1.  Li

 Li; Explanation:

Among all the alkali metal ions, Li+ is the smallest and thus it has the highest charge density. As a result, Li⁺ attracts water molecules more strongly than any other alkali metal cation and forms hydrated salts.

Question 140. Which one of the alkaline earth metal carbonates is thermally the most stable? 

1. MgCO₃
2. CaCO₃
3. SrCO₃
4. BaCO₃
   

Answer:  4. BaCO₃

BaCO₃; Explanation:

Among all the alkaline earth metals, the Ba²⁺ ion is the largest. Again, CO₃^2- ion is also quite large. Thus, among the given carbonates, Ba²⁺ and CO₃^2-  ions are most tightly packed in the crystal lattice of BaCO₃. Consequently, the lattice enthalpy of BaCO₃ is the highest and so, is most thermally stable.