ECAT Chemistry — Solutions
Solutions is part of the Chemistry section of the UET ECAT (30 of the 100 MCQs). It breaks into 3 subtopics, and we hold 32 ECAT-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (3)
How Solutions is tested
Across the 7 ECAT past papers on ParhaiKrlo, Solutions accounts for 11 questions. It appears in 4 of them, about 2.8 questions a paper. The heaviest was ECAT Past Paper 02, with 4 questions, and the most recent is ECAT Past Paper 07, with 3.
| Paper | Questions |
|---|---|
| ECAT Past Paper 07 | 3 |
| ECAT Past Paper 03 | 2 |
| ECAT Past Paper 02 | 4 |
| ECAT Past Paper 01 | 2 |
Solutions MCQs from the ECAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · ECAT Past Paper 07 · Solutions
The bubbling of gas from a soda drink when the bottle is opened is best explained by:
- A.Gas diffusing from the liquid into the surroundings
- B.Gas diffusing from the surroundings into the liquid
- C.The low density of the gas compared to the liquid
- D.The decreased pressure above the liquid, which lowers the solubility of the dissolved gas
Show answer
Answer: D. The decreased pressure above the liquid, which lowers the solubility of the dissolved gas — CO₂ is dissolved under pressure (Henry's law); opening the bottle lowers the pressure, so the excess gas comes out of solution as bubbles.
- Q2 · ECAT Past Paper 03 · Solutions
Which of the following is NOT a colligative property?
- A.Osmotic pressure
- B.Elevation of boiling point
- C.Freezing point
- D.All of these
Show answer
Answer: C. Freezing point — Osmotic pressure and boiling-point elevation are colligative; the freezing point itself is not (its depression is).
- Q3 · ECAT Past Paper 02 · Solutions
Which pair of liquids forms a nearly ideal solution?
- A.Water and hydrochloric acid
- B.Water and ethanol
- C.Benzene and toluene
- D.Acetone and chloroform
Show answer
Answer: C. Benzene and toluene — Benzene and toluene are similar non-polar molecules, so their mixture obeys Raoult's law closely.