Answer: Aluminum, Antimony, Arsenic, Bismuth, Carbon, Cadmium, Chromium, Cobalt, etc.
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 (a) is the correct option.
Explanation:
In order to travel, sound does need a medium. The more closer the particles of a medium, the better sound can travel through it. Therefore, in solids sound travels very quickly because in solids particles are closer to each other. As a result, they can easily transmit the energy from one particle to another.
Thus, it becomes easier for sound to travel through it. On the other hand, in solids sound can travel in both longitudinal and transverse waves.
Hence, out of the given options, sound travels in transverse waves requires a medium to travel through is the correct option.