Explanation
1) Phosphorus is a highly reactive element and, as a result, is never found on Earth as a free element.
2) Elemental phosphorus comes in various allotropes (different crystal structures) including white, red, violet, and black phosphorus.
3) The two major forms of phosphorus are white and red.
The formulae for mineral borax is :
$$Na_2B_4O_7 · 10H_2O$$
Mineral Borax is also easily converted to boric acid and other borates, which have many applications.
When mineral borax is added to a flame, it produces a yellow green color. Borax is not used for this purpose in fireworks due to the overwhelming yellow colour of sodium. Boric acid is used to colour methanol flames a transparent green.
Ammonium iron(II) sulphate, or Mohr's salt, is the inorganic compound with the formula $$(NH_4)_2Fe(SO_4)_2·6H_2O$$. Containing two different cations, $$Fe^{2+}$$ and $$NH_4^{+}$$. It is classified as a double salt of ferrous sulphate and ammonium sulphate.
So Mohr's salt contains 6 water molecules.
Hence option $$B$$ is correct.
Due to its small size and similar charge/mass ratio, boron differs from other group 13 members, but it resembles closely with silicon, the second element of group 14 to exhibit diagonal relationship. Some important similarities between boron and silicon are:
a) Both of them do not form cation and form only covalent compounds.
b) Both exists in amorphous and crystalline state and exhibit allotropy.
Boron can be prepared in several crystalline and amorphous forms. Well known crystalline forms are α-rhombohedral, β-rhombohedral, and β-tetragonal.
Boron is classified as a metalloid while the rest are considered post-transition metals. Most of the elements in the boron group show increasing reactivity as the elements get heavier in atomic mass and higher in atomic number. Boron, the first element in the group, is generally unreactive with many elements except at high temperatures. Hence, under normal circumstances boron does not react with water.
$$2Al+Na_2CO_3+3H_2O \rightarrow 2NaAlO_2+CO_2 +3H_2$$
So if $$Al$$ is washed with washing soda it forms sodium aluminate ($$NaAlO_2$$) which is soluble in water
Hence option C is correct.
Catenation is the linkage of atoms of the same element into longer chains. Catenation occurs most readily in carbon, which forms covalent bonds with other carbon atoms to form longer chains and structures.
Explanation:
Correct Option: $$C$$
Correct Option : $$D$$
In thermite welding, aluminium dust is oxidised by the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive. Iron(III) oxide is commonly used:
$$Fe_2O_3+2Al\rightarrow Al_2O_3+2Fe$$.
So oxidation of $$Al$$ takes place in thermite welding
Hence option $$D$$ is correct.
Please disable the adBlock and continue. Thank you.
