It is called convection. When warm air, or current, moves up and disperse outwards as cold air, or current, moves into the warmer region.
When mixture of NaCl and Al₂(SO₄)₃ is allowed to react with excess NaOH, only Al₂(SO₄)₃ reacts with it and NaCl does not react with NaOH due to presence of common ion (Na⁺). On reaction gelatinous precipitate of aluminium hydroxide [Al(OH)₃] is produced. The balanced chemical reaction is represented as-
Al₂(SO₄)₃ + 6NaOH → 2Al(OH)₃ + 3Na₂SO₄
On this reaction, 0.495 g = 0.495/78 moles =6.346 X 10⁻³ moles of Al(OH)₃.
As per balanced reaction, two moles of Al(OH)₃ is produced from one mole Al₂(SO₄)₃. So, 6.346 X 10⁻³ moles of Al(OH)₃ is produced from (6.346 X 10⁻³)/2 moles=3.173 X 10⁻³ moles of Al₂(SO₄)₃= 3.173 X 10⁻³ X 342 g of Al₂(SO₄)₃=1.085 g of Al₂(SO₄)₃.
So, mass percentage of Al₂(SO₄)₃ is= (amount of Al₂(SO₄)₃/total amount of mixture)X100 = 
=74.8 %.
Answer: Option (b) is the correct answer.
Explanation:
Polarity is defined as the development of partial charges on the atoms of a molecule.
Whereas polarizability is defined as the ability or measure of how readily an electron cloud is able to get distorted. More is the polarizability more will be the electron is distorted in nature.
A dipole moment is defined as the measurement of the separation of two opposite electrical charges.
Thus, we can conclude that when the electron cloud of a molecule is easily distorted, the molecule has a high polarizability.
In order to understand the meaning of the word "indigenous" , we have to break the word as
Indi + gen + ous
Here "Gen" means birth (like genesis: generation of something)
"Ous" means bearing some properties related to something
like marvelous : having property known as marvel.
Thus indigenous means having property of place where birth was taken
Thus it is originating in a particular region
The word root "gen" means "birth," and the suffix "-ous" means "having the quality of something."
