NEET The s-Block Elements PYQs & Practice Questions

10 free NEET Chemistry questions on The s-Block Elements, starting with previous year questions (2016–2026). Tap “Show answer” to check each one. No login needed.

Topics: Biological Importance of s-Block Elements · General Characteristics of Alkali Metals · Anomalous Behaviour of Lithium · Compounds of Sodium · Flame Colors of s-Block Elements · Solvay Process · Alkaline Earth Metals - General Properties · Reactivity of Alkali Metals with Water · Compounds of Calcium · Thermal Stability of Carbonates and Bicarbonates · Physical Properties of Alkali Metals · Reducing Power of Lithium

1. Q1NEET 2026Composition of Potash Alum

   In potash alum, the ratio of K+ and SO4^2- ions is:

   • A. 2:1
   • B. 2:3
   • C. 3:2
   • D. 1:2
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   Answer: C — 3:2

   Potash alum has the formula KAl(SO4)2·12H2O, containing 1 K+ ion and 2 SO4^2- ions per formula unit. So the ratio of K+ to SO4^2- is 1:2.

2. Q2NEET 2023Metals Dissolving in Liquid Ammonia

   Given below are two statements: one labelled as Assertion A and the other is labelled as Reason R: Assertion A: Metallic sodium dissolves in liquid ammonia giving a deep blue solution, which is paramagnetic. Reason R: The deep blue solution is due to the formation of amide. In the light of the above statements, choose the correct answer from the options given below.

   • A. Both A and R are true but R is NOT the correct explanation of A.
   • B. A is true but R is false.
   • C. A is false but R is true.
   • D. Both A and R are true and R is the correct explanation of A.
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   Answer: A — Both A and R are true but R is NOT the correct explanation of A.

   Assertion A is true — sodium dissolves in liquid ammonia to give a deep blue, paramagnetic solution. However, the blue colour is due to the formation of ammoniated electrons (solvated electrons), not due to the formation of amide (which forms only in concentrated solutions and gives a bronze colour, and is diamagnetic). So Reason R is false.

3. Q3NEET 2022Alkali Metals

   Identify the incorrect statement from the following:

   • A. The oxidation number of K in KO2 is +4.
   • B. Ionisation enthalpy of alkali metals decreases from top to bottom in the group.
   • C. Lithium is the strongest reducing agent among the alkali metals.
   • D. Alkali metals react with water to form their hydroxides.
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   Answer: —

   KO2 is a superoxide where the oxidation state of K is +1, not +4 (the superoxide ion O2- has oxidation state -1/2 per oxygen). All other statements about alkali metals are correct.

4. Q4NEET 2022Properties of Alkali Metals

   Identify the incorrect statement from the following: (1) Alkali metals react with water to form their hydroxides. (2) The oxidation number of K in KO2 is +4. (3) Ionisation enthalpy of alkali metals decreases from top to bottom in the group. (4) Lithium is the strongest reducing agent among the alkali metals.

   • A. Alkali metals react with water to form their hydroxides.
   • B. The oxidation number of K in KO2 is +4.
   • C. Ionisation enthalpy of alkali metals decreases from top to bottom in the group.
   • D. Lithium is the strongest reducing agent among the alkali metals.
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   Answer: A — Alkali metals react with water to form their hydroxides.

   In KO2 (potassium superoxide), potassium has oxidation state +1 (not +4), since the superoxide ion O2- has an overall charge of -1. The other statements about alkali metals reacting with water, decreasing ionisation enthalpy down the group, and lithium being the strongest reducing agent are all correct.

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5. Q5NEET 2022Uses of Alkali Metals and Compounds

   Match List-I with List-II. List-I: (a) Li (b) Na (c) KOH (d) Cs -- List-II: (i) absorbent for carbon dioxide (ii) electrochemical cells (iii) coolant in fast breeder reactors (iv) photoelectric cell. Choose the correct answer from the options given below:

   • A. a-iv, b-i, c-iii, d-ii
   • B. a-iii, b-iv, c-ii, d-i
   • C. a-i, b-iii, c-iv, d-ii
   • D. a-ii, b-iii, c-i, d-iv
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   Answer: C — a-i, b-iii, c-iv, d-ii

   Li is used in electrochemical cells (ii) (lithium batteries). Na is used as a coolant in fast breeder reactors (iii). KOH is used as an absorbent for carbon dioxide (i). Cs is used in photoelectric cells (iv). So a-ii, b-iii, c-i, d-iv.

6. Q6NEET 2021Alkaline Earth Metal Halides

   Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is:

   • A. Beryllium chloride
   • B. Calcium chloride
   • C. Strontium chloride
   • D. Magnesium chloride
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   Answer: —

   Covalent character ∝ polarisation ∝ 1/(size of cation). Size of cation: Be2+<Mg2+<Ca2+<Sr2+, so polarisation and covalent character: BeCl2>MgCl2>CaCl2>SrCl2. BeCl2 is most covalent and soluble in organic solvents.

7. Q7NEET 2021Structure of BeCl2

   The structure of beryllium chloride in solid state and vapour phase, are:

   • A. Chain in both
   • B. Chain and dimer, respectively
   • C. Linear in both
   • D. Dimer and Linear, respectively
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   Answer: A — Chain in both

   BeCl2 is polymeric (chain structure) in solid state, and exists as a dimer in vapour phase

8. Q8NEET 2019Amphoteric Hydroxides

   Which of the following is an amphoteric hydroxide?

   • A. Mg(OH)2
   • B. Be(OH)2
   • C. Sr(OH)2
   • D. Ca(OH)2
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   Answer: A — Mg(OH)2

   Be(OH)2 is amphoteric because beryllium, being the smallest and most polarizing alkaline earth metal, shows diagonal relationship properties with aluminium, giving its hydroxide the ability to react with both acids and bases.

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9. Q9NEET 2019Water Hardness Removal Methods

   The method used to remove temporary hardness of water is:

   • A. Ion-exchange method
   • B. Synthetic resins method
   • C. Calgon's method
   • D. Clark's method
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   Answer: C — Calgon's method

   Clark's method uses calcium hydroxide (slaked lime) to remove temporary hardness of water by precipitating calcium and magnesium bicarbonates as insoluble carbonates. Ion-exchange, synthetic resins, and Calgon's method are typically used for removing permanent hardness.

10. Q10NEET 2016Compounds of Calcium

    The suspension of slaked lime in water is known as:

    • A. aqueous solution of slaked lime
    • B. limewater
    • C. quicklime
    • D. milk of lime
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    Answer: C — quicklime

    A suspension (not solution) of slaked lime Ca(OH)2 in water is called milk of lime, while the clear saturated solution is called limewater.