FSC 2nd year chemistry 2nd chapter MCQs-S-Block elements Mcqs

Chapter 2: S-block elements

In this article, the author has explained the most important chemistry MCQs from the second chapter( S-block elements ) of FSC 2nd year chemistry. All the correct answers have been bold.

1: All of these can react with ice even at -100oC except

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

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2: The pair of elements that have similar chemical properties is

1. Beryllium
2. Carbon and nitrogen
3. Lithium and Magnesium
4. Aluminum and Magnesium

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3: As the alkaline earth metals (except Be) tend to lose their valence electrons readily, they act as

1. Bases
2. Strong reducing agents
3. Weak oxidizing agents
4. Weak reducing agents

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Related: FSC 2nd year chemistry 1st chapter MCQs-Periodic classification of elements and periodicity Mcqs

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4: KO₂ is an example of

1. Normal oxide
2. Sub oxide
3. Super oxide
4. Peroxide

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5: Elements of group 14

1. From M₄^– and M⁴⁺ ions
2. Exhibit oxidation state of +4
3. Form M⁴⁺ ions
4. Exhibit oxidation state of +4 and +2

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6: All of the followings always act as bases except

1. MgO
2. BeO
3. Na2O
4. BaO

7: Noble gases are a group of elements which exhibit very

1. High chemical activity
2. High electronegativity
3. Less diamagnetic property
4. Low chemical activity

8: Which of the following is arranged in order of increasing thermal stability?

1. BaCO3 < SrCO3 < CaCO3 < MgCO3
2. MgCO₃ < CaCO₃ < SrCO₃ < BaCO₃ 
3. CaCO3 < MgCO3 < BaCO3 < SrCO3 
4. MgCO3 < CaCO3 < SrCO3 < BaCO3 
5. MgCO3 < SrCO3 <  CaCo3 < BaCO3

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9: Which one of the following is correct about stability of the given ions?

1. Sn⁴⁺ > Sn²⁺
2. Pb²⁺ > Pb⁴⁺
3. Pb⁴⁺ > Pb²⁺
4. Si²⁺ >   Si⁴⁺

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10: N forms NCl₃ whereas P can farm bath PCl₃ and PCl₅ why?

1. N atoms are larger than P atoms in size
2. P is more reactive towards Cl than N
3. P has low lying 3d orbitals, which can be used for banding but N does not 3d orbitals in its valence shell
4. None of these

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11: Which one of the following statements regarding helium is correct?

1. It is used in gas-cooled nuclear reactors
2. It is used to produce and sustain powerful super conducting magnets
3. It is used as a cryogenic agent for carrying out experiments at low temperatures
4. All are correct

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12: In case of the oxygen family (group 16)

1. The tendency for catenation decreases markedly as we go down the group
2. Maximum coordination of oxygen is four due to lack of d orbital, but that of other elements is six due to presence of d orbitals
3. The tendency to form multiple bands with C, N and O decreases as going down the group from s to Te
4. All are correct

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13: Which of the following is arranged in order of increasing melting point?

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

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14: Alkali metals are characterized by

1. Good conductor of heat and electricity
2. High oxidation potentials
3. High melting point
4. Solubility in liquid ammonia
5. 1,2
6. 1,2,4
7. 2,3,4
8. All of these

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15: The solubilities of carbonates decrease down the magnesium group due to the decrease in

1. Hydration energies of cations
2. Lattice energies of solids
3. Inter ionic interaction
4. Entropy of solution formation

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16: Following statements regarding the periodic table trends of chemical reactivity of the alkali metals and the halogens are given. Which one of these statements gives the correct picture?

1. The reactivity decrease in the alkali metals but increases in the halogens with increase in atomic number down the group
2. In both the alkali metals and the halogens the chemical reactivity decreases with increase in atomic number down the group
3. Chemical reactivity increases with increase in atomic number down the group in both the alkali metals and halogens
4. In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group

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17: Based on lattice energy and other considerations which one of the following alkali metal chlorides is expected to have the highest melting point?

1. LiCl
2. KCl
3. NaCl
4. RbCl

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18: the graph represents the variation of a property of the group II elements

What is this property?

1. Ionic radius
2. Neutron / proton ratio
3. Ionization energy
4. Rate of reaction with water

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19: The products of decomposition of Mg(NO₂)₂ are

1. MgO and NO₂
2. MgO, NO₂ and O₂
3. Mg and NO₂
4. Mg(NO₂)₂

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20: Which salts of alkali and alkaline earth metals do not decompose on heating?

1. Halides
2. Bicarbonates
3. Nitrates
4. None of these

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21: A solution of Na in liquid NH3, serves as a good reducing agent due to the reaction;

1. 2Na + 2NH₃ —> 2NaNH₂ + H₂
2. 2Na + 2H₂O —> 2NaOH + H₂
3. NaNH₂ + N₂O —> NaN₃ + H₂O
4. None of these

22: A white solid (sodium salt) on heating liberates a gas and leaves an alkaline residue. The gas turns lime water milky. The solid is

1. Na₂CO₂
2. NaHCO₂
3. NaHSO₄
4. NaNH₄HPO₄

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23: Magnesium is present in

1. Ascorbic acid
2. Chlorophyll
3. Vitamin B12
4. Hemoglobin

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24: Pick out the incorrect statements about noble gases

1. He cannot be used in preference to nitrogen to dilute the oxygen in the gas cylinders used by divers
2. Helium is used in weather balloons and airships
3. Helium is used in cryoscopy to obtain the very low temperatures required for superconductivity and lasers
4. Ar is used in metallurgical process
   
   
5. 1 and 3
6. 2 and 3
7. 1 and 4
8. 1 only

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25: The calcium salt used as a fertilizer is

1. CaC₂
2. CaCO₂
3. CaCN₂
4. CaSO₄

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26: The oxide that can never act as a reducing agent is

1. SO₂
2. CO
3. CO₂
4. NO₂

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27: The purest form of silica is

1. Quartz
2. Sand
3. Flint
4. Kieseiguhr

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28: Chlorine acts as a bleaching agent in the presence of

1. Dry ice
2. Moisture
3. Sunlight
4. Pure oxygen

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29: An element of group VIIA which does not show oxidation state equal to the group number is

1. F
2. Cl
3. Br
4. I

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30: Which of the following statement is true for the halogen hydrides, HF, HCl, HBr, HI?

1. All form intermolecular H-bonds with water in aqueous solution
2. Bond length is greatest in HF
3. HF cannot be oxidized to F₂ by any of the other halogens
4. An aqueous solution of HF is the strongest acid

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31: The strongest reducing agent amongst the followings is

1. HF
2. HCl
3. HBr
4. HI

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32: In silicon dioxide

1. There are double bonds between silicon and oxygen atoms
2. Silicon is bonded to two silicon atoms
3. Each silicon atom is surrounded by two oxygen atoms and each oxygen atom is bonded to two silicon atoms
4. Each silicon atom is surrounded by four oxygen atoms and each oxygen atom is bounded to two silicon atoms

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33: In the use of chlorine as bleaching agent, the substance that is mainly responsible is

1. HOCl
2. CL₂
3. HCl
4. None of these

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34: Excess Cl₂, during bleaching is removed by reaction with antichlor which is

1. Na₂S
2. Na₂SO₃
3. Na₂SO₄
4. Na₂S₂O₃

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35: When chlorine water is exposed to sunlight, O₂ is liberated: Hence

1. Hydrogen has little affinity to O₂
2. Hydrogen has no affinity to O₂
3. Hydrogen has more affinity to chlorine
4. It is a reducing agent

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36: The halide which fails to give a precipitate with AgNO₃ is

1. F^–
2. Cl^–
3. Br^–
4. I^–

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37: If CO₂ is passed in excess through lime water, the milkiness first formed disappears due to

1. The solution getting heated by exothermic reaction
2. Formation of water soluble calcium bicarbonate
3. Reversal of the original reaction
4. Formation of volatile calcium derivative

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38: Silica is soluble in

1. HF
2. HNO₃
3. H₂SO₄
4. HCl

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39: One can obtain a silica garden if

1. Silicon salts are grown in garden
2. Crystals of colored cations are added to a strong solution of sodium silicate
3. Silicon tetrafluoride is hydrolyzed
4. Sodium silicate solution is heated with a base

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40: Which of the following is most vaporizing?

1. HI
2. HCl
3. HBr
4. HF

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41: Which of the following statements is false?

1. He₂ does not exist
2. Radon is obtained from the decay of radium
3. The most abundant rare gas found in the atmosphere is helium
4. Xenon is the most reactive among the rare gases

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42: Identify the incorrect statement among the following:

1. Cl₂ reacts with excess of NH₃ to give N₂ and HCl
2. Silicon reacts with NaOH_(aq) in the presence of air to give Na₂SiO₃ and H₂O
3. Br2 reacts with hot and strong NaOH solution to give NaBr, NaBrO₄ and H₂O
4. Ozone reacts with SO₂ to give SO₃

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43: Which of the following oxides is amphoteric in character?

1. CO₂
2. SiO₂
3. SnO₂
4. CaO

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44: Bleaching powder loses its available chlorine on standing because

1. It changes into calcium hypochlorite and calcium carbonate
2. It changes into calcium bicarbonate and chlorine
3. It changes into calcium chlorate and calcium chloride
4. It changes into calcium chlorate and calcium carbonate

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45: What are the products formed when Li₂CO₃ undergoes decomposition?

1. LiO₂ + CO
2. Li₂O + CO
3. Li₂O + CO
4. Li₂O + CO₂

46: Sodium sulfate is soluble in water but barium sulfate is sparingly soluble because

1. The lattice energy of barium sulfate is more than its hydration energy
2. The hydration energy of sodium sulfate is more than its lattice energy
3. The lattice energy has no role to play in solubility
4. The hydration energy of sodium sulfate is less than its lattice energy

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47: In the manufacture of metallic sodium by the fused salt electrolysis (Down’s Process) a small amount of calcium chloride is added to

1. Improve the electrical conduction
2. Bring down the melt temperature
3. Increase the temperature of electrolysis
4. Stabilizes the metallic sodium

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48: Plaster of Paris has the formula

1. CaSO₄. 2H₂O
2. (CaSO₄)₂ . H₂O
3. CaSO₄.H₂O
4. (MgSO₄)₂.H₂O