Which one of the following is not a solution?
- (a)Alloy
- (b)Milk
- (c)Air
- (d)Sugar
Correct — D, Sugar. A solution is a homogeneous mixture of two or more substances. An alloy is a solid solution of metals and air is a homogeneous mixture (solution) of gases, so both are solutions. Sugar, however, is a single pure chemical compound (sucrose) — not a mixture at all — so it cannot be a solution. It is the odd one out.
- (a)Alloy — An alloy such as brass or bronze is a solid solution of two or more metals, so it is a solution — not the answer.
- (b)Milk — Milk is a mixture of water, fats and proteins; it is technically a colloid rather than a true solution, but it is still a mixture — whereas sugar is a single pure compound, making it the clearer 'not a solution'.
- (c)Air — Clean, dry air is a homogeneous mixture of nitrogen, oxygen and other gases — a gaseous solution — so it is not the answer.
A solution is a homogeneous mixture of two or more substances, such as a solid solution (alloy), a gaseous solution (air) or a liquid solution (salt in water). A pure substance made of only one kind of particle — an element or a single compound like sugar — is not a solution because there is nothing mixed into it.
Three of the four options are mixtures: an alloy is a solid solution, air is a gaseous solution, and milk is a colloid. Only sugar is a single pure compound and so not a solution of anything. Milk is the tempting trap because a colloid is not a true solution either, but sugar is the definitive answer since it is not a mixture at all.
- A solution is a homogeneous mixture; an alloy is a solid solution and air is a gaseous solution.
- Sugar (sucrose) is a single pure compound, not a mixture, so it is not a solution.
- Milk is a colloid — an emulsion of fat droplets in water — which is a mixture but not a true solution.
- True solutions are transparent and do not scatter a beam of light, unlike colloids.
- Picking milk because it is not a 'true' solution — but milk is still a mixture, whereas sugar is a pure compound.
- Forgetting that alloys and clean air both count as solutions.
Asks which option is NOT a solution; separate the pure substance (sugar) from the mixtures (alloy, air, milk).
No directly related past PYQ was found.
- practice — not a real PYQ
Which one of the following is a colloid?
- (a)sugar solution
- (b)milk
- (c)brass
- (d)common salt
Answer(b) milk — a colloidal emulsion of fat droplets in water.
- practice — not a real PYQ
An alloy is best described as a
- (a)compound
- (b)solid solution
- (c)pure element
- (d)suspension
Answer(b) solid solution — a homogeneous mixture of metals.