1: Types of Solutions

Correct answer: A. Hydrogen in palladium

Explanation: Hydrogen is a gas, whereas palladium is a solid metal. When hydrogen is absorbed in palladium, palladium acts as the solid solvent and hydrogen as the gaseous solute; this is a gas-in-solid solution, so option A is correct. Salt in water and alcohol in water have liquid solvents. In air, nitrogen is part of a gaseous mixture, so it does not provide the requested solid-solvent arrangement.

Correct answer: A. Liquid in liquid solution

Explanation: Both components are liquids, and complete mixing into one uniform layer shows that they are miscible under the stated conditions. Therefore the mixture is a liquid-in-liquid solution. A separate layer would indicate immiscibility rather than a true homogeneous solution. The other choices involve a solid or gas component.

Correct answer: A. They are not mutually miscible

Explanation: Water and oil are liquids, but they are not mutually miscible in ordinary conditions, so they separate into layers instead of forming a uniform solution. Their separation is not because both are gases or because oil is solid. Water can act as either solvent or solute depending on the mixture, so D is also false.

Correct answer: A. A true solution has uniform composition throughout

Explanation: A true solution is homogeneous, meaning its composition is uniform throughout and its dissolved particles are too small to be separately seen under ordinary conditions. It does not immediately separate into layers, and it may be solid, liquid, or gaseous. Thus uniform composition is the defining distinction.

Correct answer: A. Ternary solution

Explanation: The governing concept is classification by the number of components. A solution containing exactly three components is called a ternary solution, so option A is correct. The prefix bi- indicates two components, making option B unsuitable, while unary refers to one component and is not the correct classification here. The word ternary describes component count, not whether the solution is solid, liquid, or gaseous.

Correct answer: A. One solute and one solvent

Explanation: A binary solution is defined as a solution containing exactly two components. In the usual school-level description, these are one solute and one solvent, such as salt and water; therefore option A is correct. Three solutes plus one solvent would contain four components, and a single pure substance is not a solution. Option B does not express the standard solute–solvent composition expected in this classification.

Correct answer: A. Water is the solvent in an aqueous solution, while water is not the solvent in a non-aqueous solution

Explanation: Aqueous means that water is the solvent, regardless of whether the solute is solid, liquid, or gas. A non-aqueous solution uses a solvent other than water, such as alcohol. These terms do not determine whether the solution is homogeneous, nor do they specify that only one physical state or no solute is present.

Correct answer: A. Non-aqueous solution

Explanation: The governing distinction is the identity of the solvent. In iodine dissolved in alcohol, iodine is the solute and alcohol is the solvent. Because the solvent is not water, the mixture is classified as a non-aqueous solution, making option A correct. It is not aqueous because water is absent as the solvent. Although iodine is a solid, the mixture is not solid-in-solid because alcohol remains the liquid solvent.

Correct answer: A. Salt in water

Explanation: To solve this, identify both the solute and the solvent in each example. In salt water, salt is a solid solute and water is a liquid solvent, so option A satisfies both conditions. In brass, the solvent metal is solid; in hydrogen–palladium, palladium is a solid solvent; and in air, oxygen is gaseous rather than a solid solute. Thus only A is correct.

Correct answer: A. Homogeneous mixture of water and alcohol

Explanation: The relevant principle is classification by the physical states of the solute and solvent. Water and alcohol are both liquids and form a homogeneous mixture; one serves as the solvent and the other as the liquid solute, so option A is correct. Salt in water is solid in liquid, oxygen in water is gas in liquid, and hydrogen in palladium is gas in solid. Therefore the alternatives do not meet both conditions.

Correct answer: A. Sugar spread uniformly throughout water

Explanation: The governing concept is dissolution and formation of a homogeneous solution. When sugar dissolves, its particles separate from the crystal and distribute throughout the water at a molecular scale, so the crystals are no longer visible. The sweet taste proves that sugar remains present; therefore option A is correct. Dissolution is physical mixing, not destruction, solidification of water, or conversion of sugar into an escaping gas.

Correct answer: A. In a solid solution, the solvent is solid

Explanation: A solution is generally named solid, liquid, or gaseous according to the physical state of its solvent, which is the major component. Therefore a solid solution has a solid solvent, making option A correct; brass, with a solid metal as solvent, is a familiar example. A liquid solvent cannot define a gaseous solution, and water is not required in every solid solution. Hence B, C, and D are false.

Correct answer: A. Homogeneous solution of gases

Explanation: Air contains nitrogen, oxygen, argon, carbon dioxide, and other gases mixed uniformly on ordinary scales. Nitrogen is the major component and acts as the solvent, while the remaining gases act as solutes. Therefore air is treated as a homogeneous gas-in-gas solution, not as a liquid or solid solution.

Correct answer: A. Hydrogen in palladium

Explanation: The required pattern is gas as the solute and solid as the solvent. Hydrogen is a gas, while palladium is a solid metal that can absorb hydrogen, so option A represents gas in solid. Carbon dioxide in water is gas in liquid, oxygen in air is gas in gas, and salt in water is solid in liquid. Thus none of those distractors has the requested combination.

Correct answer: A. When metals are uniformly mixed in solid state

Explanation: A solution must be homogeneous, and an alloy can satisfy this condition when its metallic components are uniformly distributed in the solid state. Brass is a familiar example. Visible separate layers indicate a heterogeneous mixture, immediate separation from water is not an alloy solution, and the presence of only gases describes a different type of solution.

Correct answer: A. Solute dissolves and solvent is the dissolving medium

Explanation: The solute is the component that is dissolved, while the solvent is the component that provides the medium in which dissolution occurs. Usually the solvent is present in larger amount, but the essential definition is its role, not an absolute amount rule. Solutes may be solids, liquids, or gases, and a true solution is uniform.

Correct answer: A. Brass and salt water

Explanation: The first example must contain a solid solute and solid solvent, while the second must contain a solid solute and liquid solvent. Brass is a solid solution of metals, so it is solid in solid. Salt water contains solid salt dissolved in liquid water, so it is solid in liquid; therefore option A is correct. Soda water is gas in liquid, air is gas in gas, and hydrogen in palladium is gas in solid.

Correct answer: A. Soda water and hydrogen in palladium

Explanation: The first example must be gas dissolved in a liquid, and the second must be gas dissolved in a solid. Soda water contains carbon dioxide gas dissolved in liquid water, while hydrogen in palladium contains gaseous hydrogen absorbed by solid palladium. Therefore option A has the required order. Brass is solid in solid and salt water is solid in liquid, so B has the wrong categories; the remaining pairs also fail the stated sequence.

Correct answer: A. Its solvent is in solid state

Explanation: The overall state of a solution is generally determined by the state of its solvent. Therefore, a solid solution has a solid solvent, as in many alloys. The solute may be solid, liquid, or gas, so it need not be gaseous. Water is not required, and a solution by definition is homogeneous rather than always heterogeneous.

Correct answer: A. The solvent will be in gaseous state

Explanation: A gaseous solution has a gaseous solvent, because the solvent generally determines the overall state of the solution. Air is the familiar example: nitrogen is the gaseous solvent and other gases are solutes. The solute need not be solid, water cannot be a gaseous solvent under ordinary conditions, and gaseous solutions can be homogeneous.

Correct answer: A. A homogeneous solution has formed

Explanation: Complete dissolution means salt particles are distributed throughout the water rather than settling at the bottom. The absence of sediment and layers supports the conclusion that a homogeneous solution has formed. Salt has not been destroyed or become insoluble; water has also not changed into a gas. Excess undissolved salt would produce sediment.

Correct answer: A. Calling brass a gas-in-liquid solution

Explanation: The governing concept is that a solution is classified by the physical state of its solute followed by that of its solvent. Brass is an alloy containing solid metals, so it is a solid-in-solid solution, not a gas-in-liquid solution. Soda water is gas in liquid, air is gas in gas, and salt water is solid in liquid. Therefore, option A is the incorrect classification.

Correct answer: A. Oxygen in water is gas in liquid solution

Explanation: A solution is classified by the physical states of its solute and solvent. In oxygenated water, oxygen is a gas and water is a liquid, so it is a gas-in-liquid solution; hence option A is correct. Brass is a solid-in-solid alloy, air is mainly gas-in-gas, and salt water is solid-in-liquid. Thus the other classifications reverse or misidentify the component states.

Correct answer: A. Carbon dioxide in water

Explanation: Water is the solvent in every listed example, but carbon dioxide is a gas, so it is not a solid solute. Salt, sugar, and glucose are commonly treated as solid solutes in their pure states. Therefore carbon dioxide in water is the only option satisfying the condition of a non-solid solute.

Correct answer: A. Solution of water and alcohol

Explanation: A liquid solution may contain a liquid solute and a liquid solvent; the physical state of the solution is not proof that its solute is solid. Water and alcohol are both liquids, so their homogeneous mixture is a liquid-in-liquid solution. Salt, sugar, and glucose are solids dissolved in water, making them solid-in-liquid examples. Therefore, A is the only suitable choice.