It is because of inability of ns2 electrons of the valence shell to participate in bonding that
A
Sn2+ is oxidising while Pb4+ is reducing
B
Sn2+ and Pb2+ are both oxidising and reducing
C
Sn4+ is reducing while Pb4+ is oxidising
D
Sn2+ is reducing while Pb4+ is oxidising
Explanation
The inertness of s-subshell electrons
towards bond formation is known as inert pair
effect. This effect increases down the group thus,
for Sn, +4 oxidation state is more stable, whereas,
for Pb, +2 oxidation state is more stable, i.e., Sn2+ is
reducing while Pb4+ is oxidising
3
NEET 2016 Phase 1
MCQ (Single Correct Answer)
Among the following the correct order of acidity is
A
HClO2 < HClO < HClO3 < HClO4
B
HClO4 < HClO2 < HClO < HClO3
C
HClO3 < HClO4 < HClO2 < HClO
D
HClO < HClO2 < HClO3 < HClO4
Explanation
The acidic character of the oxoacids increases with increase in oxidation number of the halogen atom i.e.,
HClO < HClO2 < HClO3 < HClO4
Since the stability of the anion decreases in the order.
ClO4- > ClO3- > ClO2- > ClO–
Acid strength also decreases in the same order.
4
NEET 2016 Phase 1
MCQ (Single Correct Answer)
Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?
A
Br2 > I2 > F2 > Cl2
B
F2 > Cl2 > Br2 > I2
C
I2 > Br2 > Cl2 > F2
D
Cl2 > Br2 > F2 > I2
Explanation
Bond dissociation enthalpy decreases as the bond distance increases from F2 to I2. This is due to increase in the size of the atom, on moving from F to I.
F – F bond dissociation enthalpy is smaller then Cl – Cl and even smaller than Br – Br. This is because F atom is very small and hence the three lone pairs of electrons on each F atom repel the bond pair holding the F-atoms in F2 molecules.
The order of bond dissociation enthalpy is :
Cl2 > Br2 > F2 > I2
Questions Asked from p-Block Elements
On those following papers in MCQ (Single Correct Answer)
Number in Brackets after Paper Indicates No. of Questions