Types of Solutions: Solid, Liquid and Gas Combinations (9 Types)
Chemistry · Solutions · NEET
A solution is a homogeneous (evenly mixed) mixture. Because the solute and the solvent can each be a solid, a liquid, or a gas, there are 3 x 3 = 9 types of solutions. The state of the SOLVENT (the bigger amount) decides the name: gaseous solution, liquid solution, or solid solution. Memory hook: "solvent decides the surname" — air is a gaseous solution, soda water is a liquid solution, and brass is a solid solution.
The 3x3 grid of 9 solution types. Read down for the solute state and across for the solvent state. The column (solvent) gives the solution its name: everything in the GAS-solvent column is a gaseous solution, and so on.
Your doubts, answered
How many types of solutions are there? Why 9?
There are 9 types. The solute can be in 3 states (solid, liquid, gas) and the solvent can also be in 3 states, so 3 x 3 = 9 combinations. NCERT Table 1.1 lists one everyday example for each. NEET usually asks you to match an example (like 'humidity' or 'brass') to its type, so learn the examples, not just the number.
What decides whether a solution is called solid, liquid or gaseous?
The SOLVENT decides the name. The solvent is the component present in the larger amount, and its physical state gives the solution its state. Example: in soda water there is a lot of water (liquid) and a little CO2 gas, so water is the solvent and it is a LIQUID solution. In air there is mostly N2 gas, so it is a GASEOUS solution.
What is the difference between solute and solvent?
The solvent is present in the LARGER amount; the solute is present in the SMALLER amount and dissolves into the solvent. In salt water, water is the solvent and salt is the solute. This matters because the state of the solvent (not the solute) names the solution.
Give an example of a solid solution where the solute is a gas.
Hydrogen gas dissolved (adsorbed and stored) in a metal like palladium is a solid solution of a gas in a solid. This is a direct NCERT intext question (1.2). Here the solvent (palladium) is solid, so it is a SOLID solution even though the solute is a gas.
Is air a solution? What type?
Yes. Air is a homogeneous mixture of gases (mainly N2 and O2), so it is a GASEOUS solution — a gas dissolved in a gas. Any homogeneous mixture of gases is always a gaseous solution because gases mix in all proportions.
What are humidity, amalgam, and smoke as solution types?
These come straight from a NEET match-the-column PYQ. Humidity = water vapour (liquid, as vapour) in air (gas) = liquid in gas. Amalgam = a metal dissolved in mercury (e.g. sodium in mercury) = solid in liquid. Smoke = solid particles in a gas = solid in gas. Brass/alloys = solid in solid.
⚠️ The NEET trap ✗ For 'Humidity' students pick 'Solid in gas', and for 'Smoke' they pick 'Liquid in gas' — swapping the two. ✓ Humidity = LIQUID in gas (water vapour in air). Smoke = SOLID in gas (soot/carbon particles in air). 🧠 Humidity is watery, so it is a LIQUID in gas. Smoke is dusty/sooty, so it is a SOLID in gas. Match the everyday feel of the word to the state of the solute.
Real NEET questions
NEET 2024 (match type, NCERT Table 1.1)
Match List-I with List-II. List-I (Example): A. Humidity, B. Alloys, C. Amalgams, D. Smoke. List-II (Type of Solution): I. Solid in solid, II. Liquid in gas, III. Solid in gas, IV. Liquid in solid. Choose the correct match.
A · A-II, B-I, C-IV, D-III ✓
B · A-I, B-II, C-III, D-IV
C · A-III, B-I, C-IV, D-II
D · A-II, B-IV, C-I, D-III
Solution: Identify the solvent (larger amount) to name each type. A. Humidity = water vapour (liquid) in air (gas) = Liquid in gas = II. B. Alloys like brass = one solid metal in another solid metal = Solid in solid = I. C. Amalgam = a solid metal dissolved in liquid mercury... note NCERT here treats mercury as the solid-forming matrix, so amalgam is listed as Liquid in solid = IV. D. Smoke = solid soot particles in air (gas) = Solid in gas = III. So A-II, B-I, C-IV, D-III, which is option A.
NEET / NCERT intext 1.2
Give an example of a solid solution in which the solute is a gas.
A · Hydrogen dissolved in palladium metal ✓
B · Oxygen dissolved in water
C · Carbon dioxide dissolved in water
D · Ethanol dissolved in water
Solution: A solid solution needs a SOLID solvent. Palladium (a solid metal) can absorb and hold hydrogen (a gas) inside its lattice, giving a solid solution of a gas in a solid. The other options have a liquid solvent (water), so they are liquid solutions, not solid solutions.
Solved Solutions NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A solution is a mixture where two or more substances are mixed so evenly that you cannot see separate parts — it is homogeneous. Salt water and air are both solutions.
Why are there exactly 9 types of solutions?
Because matter has 3 states (solid, liquid, gas). The solute can be any of the 3, and the solvent can be any of the 3, giving 3 x 3 = 9 possible combinations.
Which type of solution does NEET ask about most?
NEET rarely tests the theory alone. It gives a match-the-column question with examples like humidity, alloys, amalgams, and smoke, and you must label each with the correct solid/liquid/gas combination from NCERT Table 1.1.
Does NEET focus more on this or on concentration units?
After this basic classification, NEET spends far more marks on concentration units (mass %, ppm, molarity, molality) and on Raoult's law. So learn the 9 types quickly, then move to concentration units next.
