Solutions

Water and ethanol are both liquids at room temperature and can mix uniformly, producing a liquid-in-liquid solution. In oxygen in water, the components are gas and liquid; in salt in water they are solid and liquid; and in hydrogen in palladium they are gas and solid. Therefore only water and ethanol have components initially in the same physical state.

The solution’s overall state generally follows the state of its solvent. Therefore a liquid solution has a liquid solvent, a gaseous solution has a gaseous solvent, and a solid solution has a solid solvent. Water is not the solvent in every solution; gases, metals and other liquids can also act as solvents. Thus option B is the correctly linked statement.

The term ternary refers to a system containing three components. Therefore a solution made of three components may be called a ternary solution. Binary means two components, not three. A single-component substance is not a multicomponent solution, and insolubility is unrelated to the numerical classification; the components still must form a homogeneous solution.

The prefix “bi-” means two, so a binary solution contains exactly two components. Usually, these are one solute and one solvent, such as salt and water in a simple salt solution. The word binary does not mean two phases or two physical states; it specifically refers to the number of components. Therefore, the correct answer is two.

The naming rule lists the solute state first and the solvent state second. Therefore, a gaseous solute dissolved in a solid solvent is a gas-in-solid solution, exactly as stated in option A. In B, C, and D, the named type reverses or changes at least one given state: solid-liquid becomes liquid-solid, liquid-gas becomes gas-liquid, and gas-liquid becomes liquid-gas.

An aqueous solution is one whose solvent is water, regardless of whether the solute is solid, liquid, or gas. In glucose in water, glucose is the solute and water is the solvent, so the resulting solution is aqueous. Iodine in alcohol is an alcoholic, non-aqueous solution; brass is a solid alloy and air is a gaseous mixture. Thus A is correct.

Water is not required for every solution; the essential condition is a homogeneous mixture. Copper and zinc can combine uniformly in the solid state to form brass, which is a solid solution or alloy and contains no water. Salt water, sugar water, and oxygen in water all explicitly use water as the solvent. Therefore, option A demonstrates a water-free solution.

A solution is a homogeneous mixture, and its physical state depends on the states of its components. Solutions can therefore be solid, liquid, or gaseous: brass is a solid solution, salt water is liquid, and air is gaseous. Water is not the only possible solvent, and the solute may be a gas or liquid as well as a solid. Thus A corrects the misconception.

The governing method is classification by the solute, solvent, and their physical states. First identify which substance dissolves and which substance is the medium. Then determine whether each is a gas, liquid, or solid and express the type in solute-in-solvent order, such as gas in liquid. This works for aqueous, non-aqueous, gaseous, solid, and alloy solutions. Colour or memory alone cannot reliably determine the type, so A is correct.

The governing concept is classification by the states of solute and solvent. Oxygen is present in the smaller amount, so it is the gaseous solute. Nitrogen is also a gas and is the main medium, so it acts as the gaseous solvent. A uniform mixture of a gaseous solute in a gaseous solvent is therefore a gas-in-gas solution, making B correct. A requires a liquid solvent, C a solid solvent, and D a liquid solute, none of which is present.

The governing concept is dissolution as a physical change and the uniform distribution of particles. Sugar is not destroyed; its particles separate from one another and spread among the water particles, becoming too small and dispersed to see individually. Because the sugar particles and their taste-producing properties remain, the solution is sweet. Water does not transform into sugar, and solutions can have many tastes, so B is the only scientifically correct explanation.

The governing concept is that the physical state assigned to an ordinary solution generally follows the state of its solvent. Carbon dioxide is the gaseous solute, but water is the liquid solvent and continuous medium. Therefore carbonated water is treated as a liquid solution. The presence of a gas as solute does not make the whole solution gaseous, and it certainly does not make it solid or plasma. Hence B is correct.

Brass is an alloy in which copper and zinc are distributed uniformly throughout the material while the mixture remains in the solid state. A solid solution therefore has a solid solvent and solute mixed at the particle level without separate visible layers. Water, gas release, and the presence of only zinc do not explain brass’s classification. Hence option A is correct.

Ethanol and water are both liquids. Because they mix completely and form a uniform phase, the mixture is classified according to the physical states of its components as a liquid-in-liquid solution. One liquid functions as the solute and the other as the solvent. No solid or gas is involved, so options B, C, and D do not fit. Option A is correct.

Hydrogen is a gas and palladium is a solid metal. When hydrogen is absorbed into palladium, hydrogen serves as the gaseous solute and palladium serves as the solid solvent, giving a gas-in-solid solution. Salt and sugar in water are solid-in-liquid examples, while ethanol in water is liquid-in-liquid. Therefore, option A is the only suitable example.

An aqueous solution is defined by the identity of its solvent: water must be the solvent. The solute may be a solid, liquid, or gas, so it is not necessarily gaseous. Dissolved solute particles usually cannot be seen separately, and the solution is not always solid. Thus the defining condition is stated in option A, making it correct.

A non-aqueous solution is one in which water is not the solvent. Iodine can dissolve in ethanol, so ethanol acts as the solvent and the resulting solution is non-aqueous. In salt water, sugar water, and oxygenated water, water is the solvent; therefore those are aqueous solutions. Hence option A is the correct example.

In salt water, salt is the solute and water is the solvent. For an ordinary solution, its physical state is generally identified from the state of the solvent; because water is liquid, the mixture is described as a liquid solution. Salt does not need to melt, no gas is produced by dissolving it, and salt water is not a solid alloy. Therefore, option A is correct.

The state of an ordinary solution is generally determined by the physical state of its solvent, which is usually present in the larger amount. When the solvent is solid, the mixture is called a solid solution; alloys such as brass illustrate this idea. The solute may be solid, liquid, or gas, while colour and pressure alone do not define the solution’s state.

Nitrogen and oxygen are both gases and mix uniformly to form a gaseous solution, as seen in the gaseous mixture called air. Sugar in water and salt in water form liquid solutions because water is the solvent. Copper and zinc can form brass, a solid alloy or solid solution. Therefore, option A correctly identifies the gaseous example.

Air is a homogeneous mixture of gases, so it is a gaseous solution and option A gives the correct match. Soda water and salt water have liquid water as their solvent, so they are liquid solutions. Brass is an alloy containing solid components and is therefore a solid solution. The remaining options mismatch the physical state of the example with the stated solution type.

Glucose dissolves in water at the particle level and becomes uniformly distributed, producing a homogeneous true solution. Chalk and sand do not dissolve molecularly; their particles may remain suspended or settle. Oil and water are immiscible and form separate layers. Thus glucose in water satisfies the defining features of a true solution: uniform composition and dissolved particles.

Water vapour is water in the gaseous state, and air is also a gaseous mixture. When water vapour spreads uniformly through air, the arrangement is gas in gas, so option A is correct. The other options involve a solid or liquid as one component. Fog is different because it contains liquid droplets dispersed in air, not water vapour mixed molecule by molecule.

A true solution is homogeneous, contains a solute and a solvent, and has particles distributed uniformly throughout its volume. The particles are extremely small and normally do not settle at the bottom, so option D is not a property of a solution. Sedimentation is associated with a suspension, while A, B and C correctly describe solutions.

A solution containing exactly two components is called a binary solution, so option A is correct. In a usual binary solution, one component is the solute and the other is the solvent. A ternary solution has three components, while a precipitate is an insoluble solid formed during a reaction or separation. “Multicomponent” is too broad to specify exactly two.