What is meant by mass defect? What is the source of energy released in nuclear fusion? [2+1]
Mass defect refers to the difference between the actual mass of an atomic nucleus and the sum of the masses of its constituent protons and neutrons, due to the conversion of mass into energy during nuclear binding.
The energy released in nuclear fusion comes from the conversion of mass into energy. When light nuclei (such as hydrogen isotopes) fuse to form a heavier nucleus (like helium), a small amount of mass is lost and converted into energy.
Question ID: 92
Uploaded on: September 14, 2024
Write with an example what is meant by the periodic property of elements. Mention a property which is not periodic. [2+1] OR What is meant by electronegativity of an element? How does the electronegativity of Group 1 elements of the long periodic table change from top to bottom ? [2+1]
A periodic property is a characteristic of elements that repeats at regular intervals when elements are arranged by increasing atomic number. Example: Atomic radius decreases across a period and increases down a group.
Mass number is not a periodic property, as it doesn't follow a regular trend across the periodic table.
OR
Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond.
In Group 1 of the long periodic table, electronegativity decreases from top to bottom as the atomic size increases, making it harder for the nucleus to attract bonding electrons.
Question ID: 93
Uploaded on: September 14, 2024
Which energy is responsible for the chemical reaction to occurs during electrolysis? What reactions do occur at the cathode and the anode during the electrolysis of acidulated water? [1+2]
The energy responsible for the chemical reactions during electrolysis is electrical energy.
At the Cathode (Reduction):
2H+ + 2e- → H2 (Hydrogen Gas)
Hydrogen ions gain electrons to form hydrogen gas.
At the Anode (Oxidation):
H2O → O2 + 4H+ + 4e-
Water molecules lose electrons to form oxygen gas and hydrogen ions.
Question ID: 94
Uploaded on: September 14, 2024
Write a balanced chemical equation with conditions for the industrial manufacture of SO3 from SO2 by the Contact process. How is H2SO4 prepared from the SO3 produced? [2+1]
SO3 (Contact Process):
2SO2 (g) + O2 (g) → 2SO3 (g)
Conditions:
Catalyst: Vanadium pentoxide (V₂O₅)
Temperature: 450°C
Pressure: 1-2 atm
Preparation of H2SO4 from SO3 :
Sulfur trioxide (SO3) is absorbed in concentrated sulfuric acid (H2SO4) to form oleum (H2S2O7) which is then diluted with water to form sulfuric acid.
2SO3 (g) + H2SO4 (l) → H2S2O7 (Oleum)
H2S2O7 (l) + H2O (l) → 2H2SO4 (l)
Question ID: 95
Uploaded on: September 14, 2024
Write a balanced chemical equation of the addition reaction of hydrogen with acetylene mentioning the conditions of reaction. Mention one use of LPG. [2+1] OR How would you convert CH3CH2OH to CH2=CH2? How is biopolymer protein biodegraded in nature? [2+1]
The addition of hydrogen to acetylene (ethyne) produces ethane. The reaction occurs in the presence of a nickel at 300° C.
C2H2 (g) + 2H2 → C2H6 (g)
One Use of LPG:
LPG (Liquefied Petroleum Gas) is commonly used as a cooking fuel in households.
OR
Ethanol (CH3CH2OH) is converted to ethene (CH2=CH2) by dehydration using concentrated sulfuric acid as a catalyst at 170ºC.
CH3CH2OH → CH2=CH2 + H2O
Biodegradation of Protein:
Proteins are biodegraded in nature by enzymes into amino acids, which are further broken down by bacteria into simpler compounds like carbon dioxide and water.
Question ID: 96
Uploaded on: September 14, 2024
What is the main component of biogas? [External Candidates WB]
The main component of biogas is methane (CH4), which typically makes up about 50-75% of the gas.
Question ID: 97
Uploaded on: September 14, 2024
What is the Sl unit of electric charge? [External Candidate]
The SI unit of electric charge is the coulomb (C).
Question ID: 98
Uploaded on: September 14, 2024
How many elements are there in the third period of the long periodic table ? [External Candidate]
There are 8 elements in the third period of the long periodic table.
Question ID: 99
Uploaded on: September 14, 2024
What is the radioactive ray that is not made up of particles ? [External Candidate]
The radioactive ray that is not made up of particles is gamma rays (γ-rays). Gamma rays are electromagnetic waves, not particles.
Question ID: 100
Uploaded on: September 14, 2024
What is the industrial source of CNG? [External Candidate]
The industrial source of Compressed Natural Gas (CNG) is natural gas, primarily composed of methane.
Question ID: 101
Uploaded on: September 14, 2024
What is the absolute scale of temperature? [External Candidate]
The absolute scale of temperature is known as the Kelvin scale. On this scale, temperature is measured in Kelvin (K), and it starts from absolute zero, which is the theoretical lowest possible temperature where molecular motion ceases. Absolute zero is defined as 0 K, equivalent to -273.15°C.
Question ID: 102
Uploaded on: September 14, 2024
Mention two advantages of AC over DC. [External Candidate]
The two advantages of AC over DC
Question ID: 103
Uploaded on: September 14, 2024