Correct Answer: Na2S
Reason:
The compound sodium sulfide i.e. Na2S is soluble in water. This compound gives strong alkaline aqueous solutions. On the other hand, the remaining three compounds i.e PbS, BaS and Fe2S3 are non-soluble in water. Often these compounds are also referred as sparingly soluble compounds.
Answer:
Crystalline solids have regular ordered arrays of components held together by uniform intermolecular forces, whereas the components of amorphous solids are not arranged in regular arrays. The learning objective of this module is to know the characteristic properties of crystalline and amorphous solids. When cleaved or broken, they produce fragments with irregular, often curved surfaces; and they have poorly defined patterns when exposed to x-rays because their components are not arranged in a regular array. An amorphous, translucent solid is called a glass.
According to Bohr, the electrons in an atom were only allowed to exist at certain energy levels. ... Just as children cannot hover between two steps on a staircase, Bohr suggested that electrons cannot hover between two energy levels in the atom. Bohr developed his energy level model further using principles from physic
B
The answer should be B.....
