Chemistry Questions and Answers

Phenolphthalein is a common laboratory indicator used to detect the presence of bases in a solution. In its basic form (pH > 8.3), it turns pink or purple, indicating the presence of a base.

The correct answer is (b). The second energy level (n=2) can hold a maximum of 8 electrons. It consists of two subshells, 2s and 2p, which can hold 2 and 6 electrons, respectively.

They completely dissociate into ions in solution. Strong electrolytes are substances that fully dissociate into ions when dissolved in water or melted. As a result, they produce a high concentration of ions in the solution, allowing for efficient electrical conductivity.

The atomic number of an element is equal to the number of protons, which in this case is 8. The mass number is the total number of protons and neutrons, which is 16. To find the number of neutrons, we subtract the atomic number from the mass number:

Number of neutrons = Mass number - Atomic number
Number of neutrons = 16 - 8
Number of neutrons = 8

So, the element has 8 neutrons.

The melting and boiling points are specific physical properties of each substance and can vary depending on the nature of the substance. Different substances have different melting and boiling points, which are determined by the strength of the intermolecular forces and the molecular structure of the substance.

The compound CCl\(_4\) is a chlorinated hydrocarbon with a central carbon atom and four chlorine atoms attached to it. According to IUPAC rules, the correct name for this compound is "tetrachloromethane."

The lanthanides and actinides are located in the f-block of the periodic table, which is a separate row placed at the bottom of the main table. These elements are also known as the inner transition metals.

Acids are substances that can donate protons (H+) in aqueous solutions. When acids react with certain metals, they can release hydrogen gas (H2) as one of the products. This is a common behavior of many acids and can be used to distinguish them from other substances.

Primary cells are non-rechargeable batteries, and the alkaline battery is a common example of a primary cell

Rusting is the corrosion of iron or steel due to exposure to oxygen and moisture in the air, resulting in the formation of iron oxide (Fe\(_2\)O\(_3\) or Fe\(_3\)O\(_4\)), which is an example of an acidic oxide.