Chemistry MCQs

In Kelvin scale of temperature, the boiling point of water is marked as

A. 212 K
B. 273 K
C. 280 K
D. 373 K

D. 373 K

In the Kelvin scale of temperature, the boiling point of water is marked as 373 K. The Kelvin scale is an absolute temperature scale and is used in many scientific and engineering applications. The Kelvin scale is based on the concept of absolute zero, which is the temperature at which all matter has zero thermal energy and is at its coldest possible state.

In Kelvin scale of temperature, the boiling point of water is marked as Read More »

The chemical formula of Chile Salt Petre is

A. CaOCl2
B. NaOH
C. NaNO3
D. CaO

C. NaNO3

The chemical formula of Chile saltpetre (also known as sodium nitrate) is NaNO3. Sodium nitrate is a white crystalline solid that is soluble in water and is used in a variety of applications, including as a fertilizer, food preservative, and oxidizing agent in the manufacture of explosives.

A. CaOCl2 is the chemical formula for calcium hypochlorite.

B. NaOH is the chemical formula for sodium hydroxide.

D. CaO is the chemical formula for calcium oxide.

The chemical formula of Chile Salt Petre is Read More »

Sodium carbonate is produced by____________?

A. haber process
B. Amonia solvay process
C. decons process
D. lead chamber process

B. Amonia solvay process

Sodium carbonate (also known as soda ash) is produced by the Ammonia solvay process. The Ammonia solvay process is an industrial process used to produce sodium carbonate from salt (sodium chloride) and limestone. It involves the reaction of sodium chloride with calcium carbonate (from limestone) in a solution of ammonia to produce sodium carbonate and calcium chloride. The sodium carbonate is then recovered from the solution by crystallization.

A. The Haber process is used to produce ammonia.

C. The Decons process is not a well-known industrial process.

D. The Lead chamber process is used in the manufacture of sulfuric acid.

Sodium carbonate is produced by____________? Read More »

Electron was discovered by?

A. Michael Faraday
B. James Maxwell
C. Yuri Gagarin
D. J.J Thomson

D. J.J Thomson

Electron was discovered by J.J. Thomson in 1897. Thomson was a British physicist and Nobel Prize winner who performed experiments with cathode rays and discovered the electron, a negatively charged subatomic particle that orbits the nucleus of an atom. This discovery was a major step in the development of our understanding of atomic structure and played a crucial role in the development of modern physics and chemistry.

A. Michael Faraday was an English scientist who made important contributions to the study of electromagnetism and electrochemistry.

B. James Clerk Maxwell was a Scottish physicist and mathematician who made important contributions to our understanding of electromagnetism and is considered one of the greatest scientists of all time.

C. Yuri Gagarin was a Soviet cosmonaut who became the first human to journey into outer space in 1961.

Electron was discovered by? Read More »

Which of the following is a substance?

A. Sea water
B. Brass
C. Tape water
D. Graphite
E. Sand

D. Graphite

All of the listed items, except “Tape water”, are substances. A substance is a material with a fixed chemical composition and defined properties, such as a specific density or melting point.

Sea water is a mixture of salt and water. Brass is an alloy made of copper and zinc. Graphite is a naturally occurring form of carbon. Sand is a naturally occurring mixture of minerals and rock fragments.

“Tape water” is not a substance, but rather a description of water used for taping purposes, such as in construction or repair work.

Which of the following is a substance? Read More »

Some substances are good conductor of electricity in both the solid and liquid states. These substances are generally______________ ?

A. ionic substances
B. metallic substances
C. molecular solids
D. covalent network solids

B. metallic substances

Metallic substances are good conductors of electricity in both the solid and liquid states. This is because metals have a large number of free electrons in their outermost energy level, which are able to move easily and carry electric current throughout the material. This property makes metals useful in electrical applications, such as wiring and electrical components.

A. Ionic substances are not good conductors of electricity in the solid state, but they can be good conductors in the molten or dissolved state because their ions are free to move and carry electric current.

C. Molecular solids are not good conductors of electricity because their molecules are held together by weak bonds and do not allow for free movement of electrons.

D. Covalent network solids are also not good conductors of electricity because their atoms are bonded covalently, forming a three-dimensional network that does not allow for free movement of electrons.

Some substances are good conductor of electricity in both the solid and liquid states. These substances are generally______________ ? Read More »

What is a mixture of Potassium Nitrate Powdered Charcoal and Sulphur called?

A. Paint
B. Glass
C. Gun Powder
D. Cement

C. Gun Powder

Gunpowder is a mixture of potassium nitrate (saltpeter), powdered charcoal, and sulfur. This mixture was invented in China over a thousand years ago and was initially used primarily in the manufacture of fireworks. Later, it was adopted for use in weapons, including firearms and cannons, due to its flammability and explosive properties. The burn rate of gunpowder can be controlled by varying the ratios of the three components, making it possible to use it for different purposes such as propelling projectiles or creating a flash and bang for special effects.

What is a mixture of Potassium Nitrate Powdered Charcoal and Sulphur called? Read More »

The diameter of an atom is in the order of________________?

A. 0.2m
B. 0.2mm
C. 0.2nm
D. 0.2pm

C. 0.2nm

The diameter of an atom is in the order of 0.2 nm (nanometers), which is equivalent to 0.0000002 mm. Atoms are extremely small and cannot be seen with the naked eye. In fact, they are so small that they are measured in nanometers or picometers (1 nm = 10^-9 m, 1 pm = 10^-12 m). The size of an atom is determined by the size of its nucleus, which is much smaller than the electron cloud surrounding it. The electron cloud is what gives an atom its overall size and determines how it interacts with other atoms and molecules.

The diameter of an atom is in the order of________________? Read More »

All of the following substances are crystalline except_____________?

A. Ice
B. Diamond
C. Sucrose
D. Plastic

D. Plastic

A crystalline substance is one that has a repeating, ordered arrangement of its atoms, molecules, or ions. This arrangement gives rise to a characteristic, repeating pattern of lattice points that can be observed under a microscope. Examples of crystalline substances include ice, diamond, and sucrose (table sugar). Plastic, on the other hand, is an amorphous substance, which means that it lacks a repeating, ordered arrangement of its atoms or molecules. This lack of order gives plastic a random, disordered structure, which can be seen as a lack of regular pattern when viewed under a microscope.

All of the following substances are crystalline except_____________? Read More »

Covalent network crystals have_____________?

A. higher melting point then molecular crystals
B. lower melting point then molecular crystals
C. discrete molecules linked by Van der waals forces
D. hydrogen bonding

A. higher melting point then molecular crystals

Covalent network crystals are solids in which the atoms are held together by covalent bonds, forming an extensive network of interconnecting bonds. Because of the strong nature of covalent bonds, covalent network crystals tend to have high melting and boiling points compared to other types of solids, such as molecular solids. In comparison, molecular solids are composed of discrete, individual molecules held together by weaker intermolecular forces, such as hydrogen bonding or van der Waals forces. As a result, molecular solids generally have lower melting and boiling points than covalent network crystals.

Covalent network crystals have_____________? Read More »

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