The P-Block Quiz-17
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Q1. Statement 1:Among chalcogens, tendency of catenation is maximum for sulphur.
Statement 2: S-S bond dissociation energy is higher then O-O bond dissociation energy.
Statement 2: S-S bond dissociation energy is higher then O-O bond dissociation energy.
Solution
Catenation means the tendency of an element to from chains of identical atoms which is pronounced in sulphur among chalcogens.
Q2.Statement 1: The van der Waals’ forces are directly proportional to the ionisation potentials
Statement 2: Van der Waals’ forces increases as the size and diffuseness of the electron clouds increases
Statement 2: Van der Waals’ forces increases as the size and diffuseness of the electron clouds increases
Solution
Van der Waals’ forces or London forces are inversely proportional to the ionisation potential of the atoms
Van der Waals’ forces or London forces are inversely proportional to the ionisation potential of the atoms
Q3. Statement 1:PCl5 is covalent in gaseous and liquid states but ionic in solid state
Statement 2:PCl5 in solid state consists of tetrahedral PCl5+ cation and octahedral PCl6+ anion
Statement 2:PCl5 in solid state consists of tetrahedral PCl5+ cation and octahedral PCl6+ anion
Solution
PCl5 is trigonal bipyramidal containing sp3d hybridised P atom in liquid and gaseous state. Whereas, in solid state it consists of tetrahedral PCl4+ cation and octahedral PCl6- anions
PCl5 is trigonal bipyramidal containing sp3d hybridised P atom in liquid and gaseous state. Whereas, in solid state it consists of tetrahedral PCl4+ cation and octahedral PCl6- anions
Q4. Statement 1: Helium and beryllium have similar outer electronic configuration of the type ns2
Statement 2: Helium and beryllium both are chemically inert
Solution
Helium is a noble gas but beryllium is a member of alkaline earth metal. Thus, beryllium is chemically active and helium is inactive
Helium is a noble gas but beryllium is a member of alkaline earth metal. Thus, beryllium is chemically active and helium is inactive
Q5.Statement 1: Oxygen is more electronegative than sulphur, yet H2S is acidic, while H2O is neutral
Statement 2: H-S bond is weaker than O-H bond
Statement 2: H-S bond is weaker than O-H bond
Solution
H-S bond is weaker than H-O bond hence, H2S is more acidic than H2O
H-S bond is weaker than H-O bond hence, H2S is more acidic than H2O
Q6. Statement 1: OF2 is named as oxygen difluoride.
Statement 2: OF2 is oxygen is less electronegative than fluorine.
Statement 2: OF2 is oxygen is less electronegative than fluorine.
Solution
The compound of oxygen and fluorine is more electronegative than oxygen fluorides as fluorine is more electronegative than oxygen
The compound of oxygen and fluorine is more electronegative than oxygen fluorides as fluorine is more electronegative than oxygen
Q7. Statement 1: White phosphorus is more reactive than red phosphorus.
Statement 2: red phosphorus consists of P4 tetrahedral units linked to one another to form linear chains.
Statement 2: red phosphorus consists of P4 tetrahedral units linked to one another to form linear chains.
Solution
White P exists as discrete P4 tetrahedral molecule having P-P-P bound angle 60°.Hence, molecule is under strain and more reactive while red P exits as P4 tetrahedral joined together through covalent bounds giving polymeric structure.
White P exists as discrete P4 tetrahedral molecule having P-P-P bound angle 60°.Hence, molecule is under strain and more reactive while red P exits as P4 tetrahedral joined together through covalent bounds giving polymeric structure.
Q8.Statement 1: Helium is the only substance that can’t be solidified at atmospheric pressure
Statement 2: The zero point energy of helium is very high
Statement 2: The zero point energy of helium is very high
Solution
Zero point energy of helium is so high that it outweighs the weak interatomic forces which are not strong enough to bind the helium atoms into the crystalline state
Zero point energy of helium is so high that it outweighs the weak interatomic forces which are not strong enough to bind the helium atoms into the crystalline state
Q9.Statement 1: Red phosphorus is less volatile than white phosphorus
Statement 2: Red phosphorus has a discrete tetrahedral structure
Statement 2: Red phosphorus has a discrete tetrahedral structure
Solution
Red phosphorus is less volatile than white phosphorus because it exists in linked tetrahedral structures.
Red phosphorus is less volatile than white phosphorus because it exists in linked tetrahedral structures.
Q10. Statement 1: The ionization energy of gallium remains nearly same as that of aluminium.
Statement 2: This is due to shielding of outer shell electrons form the nucleus by the d electrons of gallium.
Statement 2: This is due to shielding of outer shell electrons form the nucleus by the d electrons of gallium.
Solution
In Ga, 10-d electrons in penultimate shell shiled the nucleus change less effectively, the outer electrons is held frimly by the nucleus. As result, the ionisation energy remains nearly the same as that of aluminium in spite of the fact that atomic size increase.
In Ga, 10-d electrons in penultimate shell shiled the nucleus change less effectively, the outer electrons is held frimly by the nucleus. As result, the ionisation energy remains nearly the same as that of aluminium in spite of the fact that atomic size increase.
