Questions

The number of bonds between a pair of atoms is called the bond order.

Bond orders can be calculated from Lewis structures, which are the heart of the valence-bond model. Oxygen, for example, has a bond order of two.

When there is more than one Lewis structure for a molecule, the bond order is an average of these structures. The bond order in sulfur dioxide, for example, is 1.5  the average of an S-O single bond in one Lewis structure and an S=O double bond in the other.

In molecular orbital theory, we calculate bond orders by assuming that two electrons in a bonding molecular orbital contribute one net bond and that two electrons in an antibonding molecular orbital cancel the effect of one bond. We can calculate the bond order in the O₂ molecule by noting that there are eight valence electrons in bonding molecular orbitals and four valence electrons in antibonding molecular orbitals in the electron configuration of this molecule. Thus, the bond order is two.

Steel is not a compound or element. Steel is an alloy of iron and carbon and other elements and hence it is a mixture. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.

Scope, quality, and cost are the triple constraints. Quality is a function of these three areas and can impact them; however it is not considered one of the components of the triple constraint. Therefore, Answer A, B, and C are incorect.

The four bonds of carbon tetrachloride (CCl4) are polar, but the molecule is nonpolar because the bond polarity is cancelled by the symmetric tetrahedral shape. Hence, making the net dipole as zero and molecule as non-polar.

When other atoms substitute for some of the Cl atoms, the symmetry is broken and the molecule becomes polar.

A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. 

Carbon dioxide is a main greenhouse gas, found in car exhaust pipes.
Methane and nitrous oxide is another type of greenhouse gas.

Oxygen is the only clean gas out there because we need it to survive. Therefore, the only gas that is not a greenhouse gas is Oxygen.

Iconic attraction of India Taj Mahal has emerged as the 5th most popular landmark in the world and 2nd in Asia, according to the online travel portal TripAdvisor’s ‘Travellers’ Choice Awards for Landmarks. Globally, Angkor Wat in Cambodia, Sheikh Zayed Grand Mosque Center in Abu Dhabi, Mezquita Cathedral de Cordoba in Spain, and St Peter’s Basilica in Italy, bagged the first four ranks respectively. Whereas, the top 10 landmarks in Asia has been topped by Angkor Wat, followed by Taj Mahal on the second place. Apart from this, Taj Mahal has also ranked first in the list of popular landmarks in India, followed by AmberFort, Jaipur; Swaminarayan Akshardham, New Delhi, etc.