Chemistry Quiz 4

The indicator used in the titration of sodium carbonate with sulphuric acid is Methyl orange. Methyl orange is a pH indicator frequently used in titration because of its clear and distinct colour variance at different pH values. Methyl orange shows red colour in the acidic medium and yellow colour in the basic medium.

Litmus is a water-soluble mixture of different dyes obtained from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity.

Vinegar made by fermentation from cane sugar contains acetic acid. Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. It typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to ethanol using yeast, and ethanol to acetic acid by acetic acid bacteria.

The four common radioactive elements are Uranium, Radium, Polonium, Thorium, etc. Radioactive elements are made up of atoms whose nuclei are unstable and give off atomic radiation as part of a process of attaining stability. The emission of radiation transforms radioactive atoms into another chemical element, which may be stable or maybe radioactive such that it undergoes further decay.

Aluminium provides amphoteric oxide. Metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. Many metals (such as zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Al₂O₃ is an example of an amphoteric oxide.

The mercury and sodium street lamps light up because of atomic emission. An electric discharge takes place when electricity is passed through sodium vapors at low or high pressure. As a result, the valence electron present in sodium atoms becomes excited and emits light. The mercury vapor lamp works by creating an electric current to mercury vapor within a sealed glass jacket.

Gunpowder consists of a mixture of nitre (potassium nitrate), sulphur, and charcoal. Together, these materials will burn rapidly and explode as a propellant. The sulphur and charcoal act as fuels while the nitre is an oxidizer.

The lustre of the metals is because of the reflection of light due to the presence of free electrons. The free electrons can move freely in the metal causing any light incident on them to get reflected back.

Chromium is a toxic heavy metal which is found in modern tannery industries.

Carbon monoxide (CO) is the major harmful gas emitted by automobile vehicles which causes air pollution. It results from incomplete combustion of fuel and is emitted directly from vehicle tailpipes.