Chemistry - Study Mode

[#381] The common name for the compound having formal NaOH is
Correct Answer

(A) Caustic soda

Explanation

Solution: Sodium hydroxide is also known as lye or soda , or caustic soda. At room temperature, sodium hydroxide is a white crystalline odorless solid that absorbs moisture from the air.

[#382] Philosopher’s wool is chemically
Correct Answer

(C) Zinc oxide

Explanation

Solution: The compound zinc oxide (ZnO) is called philosopher's wool. Alchemists, as part of their rituals, would burn zinc in air and collect the residue, which formed into white woolly tufts. They called it lana philosophica in Latin, meaning philosopher's wool.

[#383] What is the atomic number of Oxygen?
Correct Answer

(B) 8

Explanation

Solution: The atomic number of oxygen is 8.

[#384] The iron ore magnetite consists of
Correct Answer

(A) Fe 2 O 3

Explanation

Solution: The iron ore magnetite consists of Fe 2 O 3 .

[#385] The ionisation energy of hydrogen atom in the ground state is x KJ. The energy required for an electron to jump from 2 nd orbit to 3 rd orbit is
Correct Answer

(A) 5x/36

Explanation

Solution: The ionisation energy for the hydrogen atom can be written as: Ionisation energy = energy in first orbit - energy in infinite orbit Ionisation energy =xa0u200b E = -E 0 / n 2 , where E 0 = 13.6 eV (1 eV = 1.602×10 -19 Joules) and n = 1,2,3… and so on. The difference in energy = Einfinity - E1 so the ionisation energy from the ground state = x KJ = 0-( -E 0 /1 2 ) = E 0 The energy required to jump the elctron from second to the third stage is: