Practice MCQ Questions and answers on Chemistry-GK

In 1828, german chemist Wohler prepared urea in a laboratory from ammonium cyanate. This was the first organic compound synthesized artificially from inorganic materials.

Among the following, carbonate ore of Zinc is Calamine.

Aluminium is the metal commonly used for making aircraft and rockets due to its advantageous properties. Aluminium is lightweight, which is crucial for aircraft and rocket construction to reduce fuel consumption and increase payload capacity. Additionally, aluminium has good corrosion resistance, which is important for structures exposed to harsh environmental conditions, such as those encountered during flight. Lead, nickel, and copper are not typically used for making aircraft and rockets due to factors such as weight, strength, and corrosion resistance.

Option A: Lead is not suitable for aircraft and rocket construction due to its high density and poor strength-to-weight ratio.
Option B: Aluminium is the correct choice, as explained above.
Option C: Nickel is not commonly used for aircraft and rocket construction. While nickel may be used in certain aerospace applications, it is not the primary metal used for aircraft and rockets.
Option D: Copper is also not typically used for making aircraft and rockets due to its high density and poor strength-to-weight ratio compared to aluminium.

Octane rating or octane number is a standard measure of the performance of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand. Isooctane (upper) has an octane rating of 100 whereas n-heptane has an octane rating of 0.

Double bonds are shorter than single bonds because p-orbital overlap is maximized.

The most common heterocycles are those having five- or six-membered rings and containing heteroatoms of nitrogen (N), oxygen (O), or sulfur (S). The best known of the simple heterocyclic compounds are pyridine, pyrrole, furan, and thiophene.

Duma's method can be used to estimate nitrogen in all type of organic compounds. Detection of nitrogen is done by Lassigne's test. Estimation of phosphorus is done by Carius method.

Arsenic, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, and selenium are some of the metals called ‘heavy’ because of their high relative atomic mass. They persist in nature and can cause damage or death in animals, humans, and plants even at very low concentrations.

Alkali metals such as Lithium are the most electropositive elements in the periodic table. As alkali metals have low ionization energies, they have a great tendency to lose electrons forming uni-positive ions.

The heaviest naturally stable element is uranium, but over the years physicists have used accelerators to synthesize larger, heavier elements. In 2006, physicists in the United States and Russia created element 118.