Q.1. Which of the following is not correct about carbon monoxide? (2020)
A: The carboxyhaemoglobin (haemoglobin bound to CO) is less stable than oxyhaemoglobin.
B: It is produced due to incomplete combustion.
D: It forms carboxyhaemoglobin.
D: It reduces oxygen carrying ability of blood.
CO when combine with haemoglobin it forms carboxyhaemoglobin which more stable than oxyhaemoglobin thats why it reduces oxygen carring ability of blood.
Q.2. Identify the correct statements from the following: (2020)
(a) CO2(g) is used as refrigerant for ice-cream and frozen food.
(b) The structure of C60 contains twelve six carbon rings and twenty five carbon rings.
(c) ZSM-5, a type of zeolite, is used to convert alcohols into gasoline.
(d) CO is colourless and odourless gas.
A: (b) and (c) only
B: (c) and (d) only
C: (a), (b) and (c) only
D: (a) and (c) only
⇒ CO2 (s) is not used as refrigerant for ice-cream & frozen food.
⇒ ZSM-5 zeolite used to convert alcohols into gasoline
⇒ CO is colourless & odourless gas
Q.3. Among the following, the one that is not a green house gas is (2019)
A: Nitrous oxide
D: Sulphur dioxide
Fact: SO2 (g) is not a greenhouse gas.
Q.4. Which of the following species is not stable? (2019)
Due to presence of d-orbital in Si, Ge and Sn they form species like SiF62-, [GeCl6]2-, [Sn(OH)6]2-
SiCl62- does not exist because six large chloride ions cannot be accommodated around Si4+ due to limitation of its size.
Q.5. Which one of the following elements is unable to form MF63- ion ? (2018)
Boron belongs to 2nd period and it does not have vacant d-orbital.
Q.6. The correct order of atomic radii in group 13 elements is (2018)
A: B < Al < In < Ga < Tl
B: B < Al < Ga < In < Tl
C: B < Ga < Al < Tl < In
D: B < Ga < Al < In < Tl
Atomic and ionic radii. Atomic and ionic radii of group 13 elements increase from top to bottom in the group. This is due to increase in the number of energy shells in each succeeding element. However, the atomic radius of gallium (Ga) is less than that of aluminium (Al).
It is due to the poor shielding of the valence electrons of Ga by the inner 3d-electrons. As a result, the effective nuclear charge of Ga is somewhat greater in magnitude than that of Al. Thus, the electrons in gallium experience the greater force of attraction by the nucleus than in aluminium. Hence the atomic size of Ga(135 pm) is slightly less than that of Al(143 pm).
Q.7. The species, having bond angles of 120° is :- (2017)
Q.8. It is because of inability of ns2 electrons of the valence shell to participate in bonding that (2017)
A: Sn2+ is reducing while Pb4+ is oxidising
B: Sn2+ is oxidising while Pb4+ is reducing
C: Sn2+ and Pb2+ are both oxidising and reducing
D: Sn4+ is reducing while Pb4+ is oxidising
Inability of ns2 electrons of the valence shell to participate in bonding on moving down the group in heavier p-block elements is called inert pair effect
As a result, Pb(II) is more stable than Pb(IV)
Sn(IV) is more stable than Sn(II)
∴ Pb(IV) is easily reduced to Pb(II)
∴ Pb(IV) is oxidising agent
Sn(II) is easily oxidised to Sn(IV)
∴ Sn(II) is reducing agent