Solutions

Correct answer: A. Salt in water and iodine in ethanol

An aqueous solution has water as its solvent, whereas a non-aqueous solution uses a solvent other than water. Salt dissolved in water is therefore aqueous. Iodine dissolved in ethanol is non-aqueous because ethanol is the solvent. Thus A gives the required contrast. Brass and bronze are alloys, air and nitrogen are gases, and both examples in D are water-based solutions, so they do not provide the same contrast.

Correct answer: A. A homogeneous mixture of salt, sugar, and water

The prefix ternary refers to three components. Salt, sugar, and water are three distinct substances; if they are uniformly mixed, they form a homogeneous ternary solution. Therefore A is correct. Each other option contains only two named components: salt and water, oxygen and nitrogen, or copper and zinc. Those are binary mixtures or solutions, not ternary ones.

Correct answer: A. It contains two components in total

The prefix bi- means two, so a binary solution contains exactly two components in total. In the usual case, one component acts as the solute and the other as the solvent. A binary solution may be solid, liquid, or gaseous, and it can be homogeneous. Thus A is correct, while B incorrectly claims two solvents, C restricts the state without reason, and D contradicts the meaning of a solution.

Correct answer: A. Oxygen in water

In oxygen dissolved in water, oxygen is a gas and water is a liquid. Therefore the solvent is liquid while the solute is non-liquid, making option A correct. Ethanol in water and methanol in ethanol are liquid-in-liquid mixtures. In mercury-sodium, the mercury solute is liquid but sodium is a solid solvent, so that example satisfies neither required condition.

Correct answer: A. Nature of a true solution

True-solution particles are extremely small and remain uniformly distributed, so they do not settle under ordinary conditions. A suspension contains larger particles that usually settle on standing. Settling, precipitate formation, or visible layers therefore suggest a different mixture, not the stable homogeneous nature of a true solution.

Correct answer: C. Soda water: liquid in gas

Soda water is made when gaseous carbon dioxide dissolves in liquid water. Its correct classification is gas in liquid, not liquid in gas; therefore option C is the incorrect matching. Air is gas in gas, brass is solid in solid, and salt water is solid in liquid. Remembering that the solute is named first and the solvent second prevents the reversal in option C.

Correct answer: A. A liquid-in-liquid solution may form

When two liquids mix uniformly without forming separate layers, they may be miscible and form a homogeneous liquid-in-liquid solution. Water and ethanol are a familiar example. The observation does not imply a solid solution, because no solid solvent is present, and it is not necessarily a suspension. Liquids can form true solutions, so option A is correct.

Correct answer: A. Soda water: aqueous and liquid solution

Soda water contains carbon dioxide dissolved in water. Because water is the solvent, it is an aqueous solution; because water is liquid, the overall solution is classified as liquid. Brass is a solid, non-aqueous alloy, and air is gaseous rather than solid or aqueous. Salt water is aqueous and liquid, not gaseous and solid, so B, C, and D are incorrect.

Correct answer: A. Brass, bronze, hydrogen in palladium

A solid solution has a solid solvent. Brass and bronze are solid-solid alloys, and in hydrogen-in-palladium, solid palladium acts as the solvent for hydrogen. Thus every example in A is associated with a solid solvent. B and D use liquid water as solvent, while C consists of gaseous mixtures with gaseous solvents, so those groups do not qualify.

Correct answer: A. Air and oxygen in nitrogen

The governing concept is that the physical state of a solution is generally identified by the state of its solvent. A gaseous solution has a gas as its solvent. Air is a homogeneous mixture of gases, and oxygen mixed uniformly with nitrogen has nitrogen as the gaseous solvent. In B and D, water is the liquid solvent, whereas brass and bronze in C are solid alloys. Therefore, only A contains gaseous-solution examples.

Correct answer: A. Because its solvent is water which is liquid

Soda water does contain a gas, usually carbon dioxide, but that gas is the solute. The solvent is liquid water, and the physical-state classification of the solution follows the solvent. Therefore soda water is a liquid, aqueous solution, not a gaseous solution. The other options make false claims about its composition or nature.

Correct answer: A. It is homogeneous and its particles are generally not separately visible

A true solution is homogeneous, meaning its composition is uniform throughout. Its solute particles are extremely small and generally cannot be seen separately with the naked eye, nor do they settle under ordinary conditions. Colour and thickness are not necessary properties, and every solution has a solvent.

Correct answer: A. Solid solute dissolves in liquid solvent

The governing concept is the order of the phrase: the first state describes the solute and the second describes the solvent. Consequently, a solid in liquid solution contains a solid solute dissolving uniformly in a liquid solvent, such as salt in water. B describes liquid in solid, C gas in gas, and D liquid in gas. Only A matches the requested category exactly.

Correct answer: A. Oxygen in water

Oxygen is a gas, so it acts as the gaseous solute. Water is a liquid and acts as the solvent. The broad physical category of a solution is named from the state of its solvent; therefore oxygen dissolved in water is a gas-in-liquid solution and its final form is liquid. Brass and zinc in copper are solid solutions, while camphor in nitrogen has a gaseous solvent.

Correct answer: A. Chloroform in nitrogen

Chloroform is a liquid and is the solute in this example. Nitrogen is a gas and is the solvent, so the mixture is classified as a liquid-in-gas solution and has a gaseous final form. Ethanol in water and salt in water are liquid solutions because water is the solvent. An amalgam is a solid alloy, not a gaseous solution.

Correct answer: A. Hydrogen in palladium

Hydrogen is a gas and is taken as the solute in this example. Palladium is a solid metal that serves as the solvent or host. Since the solvent is solid, the resulting homogeneous mixture is classified as a solid solution, often described as gas-in-solid. Soda water and oxygen in water have liquid solvents, while air is gas in gas.

Correct answer: A. Camphor in nitrogen

Camphor is a solid substance and is identified as the solute. Nitrogen is a gas and acts as the solvent or continuous medium. Therefore this is a solid-in-gas solution, whose final category is gaseous. Salt in water is solid in liquid, brass is solid in solid, and chloroform in nitrogen is liquid in gas.

Correct answer: A. Glucose in water

Glucose is a solid solute, while water is a liquid solvent. When glucose dissolves uniformly in water, the mixture is classified as a solid-in-liquid solution and its final form is liquid. Air is gas in gas, brass is solid in solid, and chloroform in nitrogen is liquid in gas. Thus only option A satisfies both required states.

Correct answer: A. The solvent is liquid

In the usual classification of solutions, the final physical category follows the state of the solvent, which is the continuous medium. Thus a liquid solution safely indicates a liquid solvent. The solute could instead be a solid, liquid, or gas, as in salt water, ethanol in water, or oxygen in water. A liquid solution also need not contain water, so it is not necessarily aqueous.

Correct answer: A. When states of solute and solvent are not given

The type of solution depends on the states of the solute and solvent, not simply on visible colour or appearance. If those states are not supplied, looking at a uniform sample may not reveal whether it is solid, liquid, or gaseous in classification. Homogeneity is useful for identifying a solution, but not enough to classify its state type.

Correct answer: A. They are homogeneous mixtures

A solution is a homogeneous mixture, meaning its components are uniformly distributed and every portion has the same composition at the relevant scale. Solutions may be gaseous, liquid, or solid: air, salt water, and brass illustrate these categories. Water is not essential because many solutions are non-aqueous, and a solution can contain more than two components. Therefore homogeneity is the common feature.

Correct answer: D. Separate layers of water and oil

A solution must be homogeneous, with its components uniformly distributed. Water and oil do not mix uniformly; they form separate layers because of their immiscibility, so the mixture is heterogeneous and is not normally called a solution. Completely dissolved sugar in water is a liquid solution, air is a gaseous solution, and brass is a solid solution or alloy.

Correct answer: A. Both are solid in liquid solutions

Salt and glucose are both solids before dissolving, so each acts as a solid solute. Water is the liquid solvent in both examples, and the dissolved particles spread uniformly through it. Consequently, both are solid-in-liquid solutions. Their solutes differ chemically, but their physical-state classification is the same.

Correct answer: A. Water is the solvent

The term aqueous specifically means that water is the solvent. The solute in an aqueous solution may be a solid, liquid, or gas, such as salt, ethanol, or oxygen. The resulting solution is usually liquid, not solid, and its components are uniformly mixed rather than forming separate layers. Hence water being the solvent is the only statement that applies to every aqueous solution.

Correct answer: D. Soda water is a gas-in-solid solution

In soda water, carbon dioxide is the gaseous solute, but water is the liquid solvent. Therefore soda water is a gas-in-liquid solution, not a gas-in-solid solution. Air is gas in gas, salt water is solid in liquid, and brass is solid in solid. The error in option D is the claim that the solvent is solid; it is actually liquid water.