Chemistry - Study Mode

[#116] Which of the following is chiefly present in LPG (Liquefied Petroleum Gas) ?
Correct Answer

(D) Butane

Explanation

Solution: LPG is composed mainly of propane and butane, while natural gas is composed of the lighter methane and ethane.

[#117] Candle is a mixture of
Correct Answer

(A) Paraffin was and stearic acid

Explanation

Solution: Most candles are made from paraffin wax, a byproduct of petroleum refining. Candles can also be made from microcrystalline wax, beeswax (a byproduct of honey collection), gel (a mixture of polymer and mineral oil), or some plant waxes (generally palm, carnauba, bayberry, or soybean wax).

[#118] What is the atomic number of mercury?
Correct Answer

(D) 80

Explanation

Solution: The atomic number of mercury is 80.

[#119] Which of the following molecules has a bond order of 2.5?
Correct Answer

(D) NO

Explanation

Solution: Bond order is a measure of the number of chemical bonds between two atoms in a molecule. It is calculated as (Number of bonding electrons - Number of anti-bonding electrons) / 2.

For the molecule NO (nitric oxide):

The number of bonding electrons is 5 (1 from N and 2 each from the 2 O atoms).
The number of anti-bonding electrons is 2 (1 each from the 2 O atoms).

The bond order is calculated as (5 - 2) / 2 = 3 / 2 = 1.5.

Therefore, the correct answer is Option D: NO , and it has a bond order of 2.5.

[#120] An element of atomic no. 29 belongs to
Correct Answer

(B) D-block

Explanation

Solution: Copper (Cu) has the atomic number of 29. Copper belongs to the d-block which is the collective name for Groups 3 to 12 in the periodic table. Most of the d-block elements are considered to be metals, with a common lustrous metallic appearance.