Solute and solvent

The governing idea is to identify the solute first and then determine its physical state. Carbon dioxide is a gaseous solute in water; salt is a solid solute in water; and mercury is a liquid that can dissolve in or combine with certain metals to form an amalgam-type solution. Therefore the order gas, solid, liquid is given by A. In the other options, the examples do not follow the required order or do not represent the stated solute states.

When two liquids of the same state are mixed in equal amounts, the usual larger-amount rule cannot identify the solvent and solute. Depending on context, either component may be described as the solvent or the mixture may be treated without a unique designation. In the other cases, the roles are clearer.

The governing concept is the amount-based definition used for components of a solution or homogeneous alloy. The component present in greater amount is conventionally treated as the solvent, while the component in smaller amount is the solute. Since copper is greater and zinc is smaller, zinc is the solute and copper is the solvent. Zinc is neither suspended nor precipitated because the alloy is homogeneous. Thus B is correct.

The governing idea is that a solution is classified by the physical states of its solute and solvent. In oxygen dissolved in water, oxygen is a gaseous solute and water is liquid. In hydrogen dissolved in palladium, hydrogen is also a gaseous solute, but palladium is solid. Thus the solute state remains gas while the solvent state changes from liquid to solid, making A correct. In B and D both solvents are liquid.

The governing concept is the distinction between a solute and a solvent and their physical states. In salt dissolved in water and oxygen dissolved in water, water is the solvent in both cases, and it is liquid. Salt is a solid solute, whereas oxygen is a gaseous solute, so the solute state changes while the solvent state remains the same. Therefore B is correct. The other pairs mix different solvent states or do not satisfy both conditions.

A mixture’s components are the distinct substances present, whether they are dissolved or serve as the medium. Here the substances are water, salt, and sugar, so the total is three components. Water is present in the larger continuous amount and dissolves both salt and sugar; therefore it is the solvent. Salt and sugar are solutes. Hence B is correct, while A omits water and C and D wrongly call a solute the solvent.

The larger-amount rule is a useful general guide, but if two liquids are present in nearly equal amounts, it does not clearly identify one as the solvent. The stated context or conventional choice may then be needed. A single component is not a solution, and undissolved solids or layers indicate non-uniformity.

The governing concept is that the solvent is the component present as the continuous medium, and its physical state determines the solution category. In brass, the solvent is a solid metal; in hydrogen dissolved in palladium, palladium is solid; and in an amalgam, the metallic solvent is solid. The other options include liquid water or gaseous air and nitrogen as solvents, so only A is correct.

The governing rule is that the first component named is the solute and the second component is the solvent. In gas in solid, gas is the solute and solid is the solvent; in solid in gas, solid is the solute and gas is the solvent. Checking the solvent state therefore distinguishes them reliably. Colour and temperature are not the defining classification criteria, so B and C are unsuitable and D is false.

A solution is classified largely by the state of its solvent, which forms the continuous medium. In camphor in nitrogen, camphor is the solid solute and nitrogen is the gaseous solvent, so the final solution is gaseous. Hydrogen in palladium and copper in gold are solid solutions because their solvents are solids, whereas glucose in water is a liquid solution. Hence A is correct.

The governing idea is that a solution is classified by its overall state, usually the state of its solvent, while the solute may have a different state. In salt water, salt is a solid solute and water is liquid; in oxygenated water, oxygen is a gaseous solute and water is liquid. Thus both are liquid solutions, but the solute states differ. The other pairs do not meet both conditions.

A solution’s overall state is determined mainly by its solvent. Air is a gas-in-gas solution, so its solute components are gases. In chloroform dissolved in nitrogen, chloroform is a liquid solute and nitrogen is a gaseous solvent; the resulting solution is gaseous. Therefore both solutions are gaseous, but their solute states differ. The other pairs are liquid or solid solutions.

The relevant principle is that the final solution can be solid even when the solute is not solid, because the solid solvent determines the overall state. Brass is a solid alloy containing solid metallic components. Hydrogen dissolved in solid palladium forms a solid solution, although hydrogen is a gas. Thus both examples are solid solutions, while their solute states are different. The remaining pairs are not both solid.

The governing rule is that the solvent is the medium in which the solute dissolves, while the solution is named by the states of both components. Palladium is a solid metal that can absorb hydrogen; therefore hydrogen is the gaseous solute and palladium is the solid solvent. This makes A a gas-in-solid solution. B is gas in liquid, C is gas in gas, and D is solid in liquid.

When two components are in the same physical state, the component present in the larger amount is generally identified as the solvent, and the smaller component as the solute. Brass is a solid alloy containing more copper and less zinc. Therefore copper is the solid solvent and zinc is the solid solute, making A correct. It is not a liquid solution or a solid-in-gas solution.

The governing rule is that the phrase “liquid in solid” names the solute first and the solvent second. Therefore, the solute must be liquid and the solvent must be solid, with uniform mixing expected in a true solution. Option A states exactly this. B describes solid in liquid, C describes gas in liquid, and D describes liquid in gas.

The key rule is to identify the solvent in every example, not simply the solute. In option A, water is the solvent in all three cases—salt in water, ethanol in water, and carbon dioxide in water—and water is liquid. Option B and much of D involve solid metallic solvents, while C contains gaseous solvents such as air and nitrogen. Hence A is the only complete group.

A reliable method is to separate the task into three steps: identify what dissolves, identify the dissolving medium, and note the state of each. The solvent state gives the broad solution category. Memorized names, colour, or assuming that every solution contains water can all lead to errors, especially with alloys, air, and gaseous solutions.

In the expression “solid in liquid,” the first word identifies the solute and the second identifies the solvent. Therefore the solute is solid and the solvent is liquid. Option B reverses both states. Option C describes gas in liquid rather than liquid in gas, and option D also reverses the states required by gas in solid.

Soda water has gaseous carbon dioxide as solute and liquid water as solvent, so its pair is gas–liquid. Brass is a solid alloy in which both the solute and solvent components are solids, giving solid–solid. The other options reverse or misstate the states of soda water, air, hydrogen in palladium, or salt water.