S Block Previous Year Questions with Solutions are given here. BYJU’S provides accurate solutions prepared by our specialized experts. S block elements are elements of group 1 and group 2 of the modern periodic table. The s block elements having only one electron in their s-orbital are called group one or alkali metals, whereas the s block elements having two electrons filling their s-orbital are called group two or alkaline earth metals.
S block comprises 14 elements. They are hydrogen (H), lithium (Li), helium (He), sodium (Na), beryllium (Be), potassium (K), magnesium (Mg), rubidium (Rb), calcium (Ca), cesium (Cs), strontium (Sr), francium (Fr), barium (Ba), and radium (Ra). The main topics in this chapter are alkali metals, oxides and hydroxides, Halides, anomalous properties of lithium and some important compounds of calcium, etc. Students can easily download the questions and solutions in PDF format.
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JEE Main Chemistry S Block Previous Year Questions With Solutions
1. The correct statement for the molecule, CsI3, is :
(1) it contains Cs3+ and I– ions
(2) it contains Cs+, I– and lattice I2 molecule
(3) it is a covalent molecule
(4) it contains Cs+ and I3– ions.
Solution:
CsI3 -> Cs+ + I3–
CsI3 contains Cs+ and I3–.
Hence option (4) is the answer.
2. Which of the following statements about Na2O2 is not correct?
(1) Na2O2 oxidises Cr3+ to CrO42- in acid medium
(2) It is diamagnetic in nature
(3) It is the super oxide of sodium
(4) It is a derivative of H2O2
Solution:
Na2O2 is sodium peroxide. It is not super oxide.
Hence option (3) is the answer.
3. The metal that cannot be obtained by electrolysis of an aqueous solution of its salt is
1) Cr
2) Ag
3) Ca
4) Cu
Solution:
Ca cannot be obtained by the electrolysis of an aqueous solution of its salt.
Hence option (3) is the answer.
4. Based on lattice energy and other considerations, which one of the following alkali metal chloride is expected to have the highest melting point ?
(1) RbCl
(2) LiCl
(3) KCl
(4) NaCl
Solution:
NaCl has the highest lattice energy and thus the highest melting point.
Hence option (4) is the answer.
5. A metal M on heating in nitrogen gas gives Y. Y on treatment with H2O gives a colourless gas which when passed through CuSO4 solution gives a blue colour, Y is :
(1) NH3
(2) MgO
(3) Mg3N2
(4) Mg(NO3)2
Solution:
Magnesium, when heated with nitrogen, forms magnesium nitride.
3Mg + N2 → Mg3N2
Magnesium nitride reacts with water to form ammonia and magnesium hydroxide.
Mg3N2 → Mg(OH)2 + NH3
When ammonia gas is passed through CuSO4 solution, blue colour is obtained.
Hence option (3) is the answer.
6. Which one of the following will react most vigorously with water?
(1) Li
(2) K
(3) Rb
(4) Na
Solution:
Reactivity of s block elements increases down a group. So Rubidium will react most vigorously with water.
Hence option (3) is the answer.
7. Hydrogen bomb is based on the principle of
(1) Nuclear fission
(2) Natural radioactivity
(3) Nuclear fusion
(4) Artificial radioactivity
Solution:
Hydrogen bomb is based on the fusion of isotopes of hydrogen.
Hence option (3) is the answer.
8. Amongst LiCl, RbCl, BeCl2 and MgCl2 the compounds with the greatest and the least ionic character, respectively are :
(1) RbCl and MgCl2
(2) LiCl and RbCl
(3) MgCl2 and BeCl2
(4) RbCl and BeCl2
Solution:
Because of the smallest cationic size BeCl2 is least ionic. Rb+ has the biggest ionic size. So it has the greatest ionic character.
Hence option (4) is the answer.
9. In curing cement plasters water is sprinkled from time to time. This helps in
(1) developing interlocking needle-like crystals of hydrated silicates.
(2) hydrating sand and gravel mixed with cement
(3) converting sand into silicic acid
(4) keeping it cool
Solution:
During hydration of calcium aluminosilicates, cross links are developed
Hence option (1) is the answer.
10. K02(potassium super oxide) is used in oxygen cylinders in space and submarines. This is because it
(1) absorbs C02 and increases 02 content
(2) eliminates moisture
(3) absorbs C02
(4) produces ozone
Solution:
2KO, + 2H20 —> 2KOH + H202 + 02. It eliminates moisture.
Hence option (2) is the answer.
11. A metal M readily forms its sulphate MS04 which is water soluble. It forms its oxide MO which becomes inert on heating. It forms an insoluble hydroxide M(OH)2 which is soluble in NaOH solution. Then M is
(1) Mg
(2) Ba
(3) Ca
(4) Be
Solution:
Because of its small size, Beryllium shows anomalous properties with alkaline earth metals.
Hence option (4) is the answer.
12. The substance not likely to contain CaC03 is
(1) calcined gypsum
(2) sea shells
(3) dolomite
(4) a marble statue
Solution:
The composition of gypsum is CaS04. 2H20.
Hence option (1) is the answer.
13. Several blocks of magnesium are fixed to the bottom of a ship to
(1) make the ship lighter
(2) prevent action of water and salt
(3) prevent puncturing by under-sea rocks
(4) keep away the sharks
Solution:
Magnesium provides cathodic protection and prevents corrosion.
Hence option (2) is the answer.
14. The first ionization potential of Na is 5.1 eV. The value of electron gain enthalpy of Na+ will be
1) -2.55 eV
2) -5.1 eV
3)-10.2 eV
4) +2.55 eV
Solution:
Ionisation potential of alkali metal atom and electron affinity of its monocovalent cation are same in magnitude, but with opposite signs.
Hence option (2) is the answer.
15. In Zeolites and synthetic resin method, which will be more efficient in removing permanent hardness of water.
(1) Synthetic resin method as it exchanges only cation.
(2) zeolite resin method as it exchanges only cation.
(3) Synthetic resin method as it exchanges only anion.
(4) Synthetic resin is harmful to nature.
Solution:
The synthetic resin method will be more efficient in removing the permanent hardness of water because it exchanges only cation.
Hence option (1) is the answer.
Other Important Concepts:
- S Block elements
- S Block elements JEE Advanced Previous Year Questions
- Alkali Metals
- Alkaline Earth Metals
- Electron Configuration
- Electronegativity
s-block Elements – Important Topics
s-block Elements – Important Questions
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