Question Discussion & Solution

The correct answer is Monaco.

• As of June 2020, Monaco has the highest population density.

Key Points

• Monaco is the world’s second-smallest country.
• It has a population density of 26,150.3 residents per square kilometre.
• Monaco is famous for the Monte Carlo casino and for hosting the Monaco Grand Prix Formula One race.

Additional Information

• Population density is the total number of individuals present in per unit area.

Concept

Size of element:

• The atomic size of an element is determined by the atomic radius of an element.
• Atomic radius is the distance between the center of an atom to its outermost (valence) shell having electrons.
• The atomic size of any element is mentioned in form of Atomic radius.
• Unit of Atomic radius is Amstrong (A^o).

Valency of an element:

• Valency is the combining capacity of an atom of an element.
• It is otherwise the valence electrons an atom uses to form a chemical bond.

The molar mass of the element:

• It is defined as the mass of one atom of an element.
• The unit is g/mol.
• For all substances, the molar mass of in g/mol is numerically equal to the formula mass in atomic mass units.

Explanation:

• The maximum number of univalent atoms that may combine with an atom of the element is the Valency.
• The valency of an element is always an integer.
• With regard to covalent compounds, the term valency describes the number of bonds usually formed by each element.
• In ionic compounds, often, the number of positive or negative charges that appear on the atom in its ion helps to state its valency.
• The chemical behavior is largely influenced by the valency of the element.

Hence, Valency of an element is the property that determines an element's chemical behavior.

Ser - Ajmer is not correctly matched.

• Ser is located in the Sirohi district of Rajasthan.

Additional Information

• The Aravali range virtually runs across as a beam across Rajasthan and bisects the state into two major parts: Southeast Rajasthan and Northwest Rajasthan.
• Aravali range is approximately 692 Kms long, running across Gujarat, Rajasthan, Haryana, and Delhi.
• As a result, Rajasthan has multiple peaks.
• Top Peaks of Rajasthan

Concept:

• Social evils or social issues are referred to any undesirable condition that is opposed by society or by a section of society.
• Some major issues are the caste system, poverty, dowry system, child labour, religious conflicts, etc.

Explanation:

Child labour:

• Child labour refers to the exploitation of children through any form of work that deprives children of their childhood.
• Any activity that interferes with their ability to attend regular school, and is mentally, physically, socially and morally harmful.
• Child Labour (Prohibition and Regulation) Act was enacted by the Ministry of Law and Justice on 30th July 2016.
• This Act amended the Child Labour (Prohibition and Regulation) Act, 1986.
• According to this Act:
  • No child shall be employed or permitted to work in any occupation or process.
  • Criteria of a child - A person below the age of 14 yrs.
• Although these laws do not consider all work by children as child labour.
• Exceptions include work by child artists, family duties and supervised training.
• Child labour is more prevalent in the cities where the standard of living is high and children have to work to support their families.

Dowry System:

• Dowry, or the custom of accepting gifts by the bridegroom’s parents from to bride’s parents as part of a marriage settlement.
• Dowry is the money, valuables, goods, estate or property which the bride party gives to the groom's party in exchange for marriage.
• The Dowry system is most prevalent in village areas where people are uneducated and a girl is considered as a burden on their family.
• With upcoming times, this practice is not that common in urban areas.
• To prevent the system of dowry, The Dowry Prohibition Act, 1961 was enacted.

Important Points

• Both child labour and the dowry system are social evils.
• They both are punishable offences.

Thus, 

Dowry and child labour are punishable offences: Correct

Dowry and child labour are necessary evils: Incorrect

Dowry and child labour are common in the villages: Incorrect

Dowry and child labour are common in cities: Incorrect

The correct answer is Natural Gas.

Key Points

•  Fossil Fuel: Fossil Fuels are the fuels generated from the residues of living organisms (which remained buried under the earth for millions of years).
  • Examples: Coal, Petroleum, and Natural gas.
  • They are also known as Non-Renewable Natural Resources.​

 Additional Information

• Natural Gas: It is considered the best fuel because of the inflammable nature of its constituents(83% methane and 16%ethane).
  • It is used in the production of artificial chemical fertilizers. 
• Coke: It is obtained by the strong heating of coal in the absence of air as a residual substance. 
  • It contains 80-85% carbon.
  • Coke is used in the extension of metals as a reducing agent.
• Producer Gas: It is a mixture of nitrogen and carbon monoxide(in 2:1 ratio).
  • It is used in the manufacture of glass and for metallurgy.