Practice MCQ Questions and answers on Chemistry-GK

One of the two chemical methods starts from natural manganese dioxide and converts it using dinitrogen tetroxide and water to manganese nitrate solution. Evaporation of the water leaves the crystalline nitrate salt. At temperatures of 400°C, the salt decomposes, releasing N2O4 and leaving a residue of purified manganese dioxide.

In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength. The working temperature of vulcanized rubber is enhanced up to 100°C. It has good resistance to organic solvents.

The compounds formed when hydrogen combines with p-block elements are called molecular hydrides.

In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength.

In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength.

In arc welding, Argon is used as a shielding gas because it is chemically inert and forms no compounds. At the high temperatures that welding requires, the metals being welded become highly reactive to the elements in the atmosphere. Contamination from these elements can lead to brittle welds and instability in the welding arc. So,argon and other inert gases are sprayed.

Heliox is a breathing gas composed of a mixture of helium (He) and oxygen (O2). Heliox has been used medically since the 1930s, and although the medical community adopted it initially to alleviate symptoms of upper airway obstruction, its range of medical uses has since expanded greatly, mostly because of the low density of the gas

Seaweed is rich in iodine, a trace element essential for healthy thyroid function and a healthy metabolism. Iodine is particularly vital for pregnant and lactating women. Seaweed also contains zinc and antioxidants, which help strengthen immunity.

Silica gel is a desiccant, or drying agent, that manufacturers often place in little packets to keep moisture from damaging certain food and commercial products. You may have seen silica packets in everything from beef jerky to the new shoes you bought.

Silicon is a semiconductor.