Which of the following statements about the Oort Cloud is incorrect?
AIt is a theoretical spherical shell of icy bodies surrounding our solar system
BIt extends approximately 100,000 to 200,000 AU from the Sun
CIt is the primary source of long-period comets
DIt has been directly observed through telescopes and contains approximately 1 trillion objects
Correct Answer:
D. It has been directly observed through telescopes and contains approximately 1 trillion objects
Explanation:
The Oort Cloud remains theoretical and has never been directly observed; we infer its existence from comet trajectories and orbital studies.
While estimates suggest it contains billions to trillions of icy bodies, these objects are too distant and too small to be directly observed with current technology, making option D the incorrect statement among the given choices.
Which of the following compounds exhibits both ionic and covalent bonding characteristics and is commonly used in coordination chemistry?
ASodium chloride
BPotassium hexacyanoferrate(III)
CCarbon dioxide
DCalcium oxide
Correct Answer:
B. Potassium hexacyanoferrate(III)
Explanation:
Potassium hexacyanoferrate(III) contains both ionic bonds (between K⁺ and the [Fe(CN)₆]³⁻ complex) and covalent bonds (between Fe and CN ligands, and within the CN groups).
This complex salt is extensively used in coordination chemistry and analytical procedures like the Prussian blue test.
