NEET (UG)

Practice Test 1 — Solutions

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct & Statement-based)

Question 1

Which is temperature-independent?

Solution: Molality is mass-based, temperature-independent.

Question 2

Raoult's law for the solvent (non-volatile solute) is:

Solution: $p = p_A^{\circ} x_A$.

Question 3

An ideal solution has $\Delta V_{mix}$ equal to:

Solution: Ideal: $\Delta V_{mix}=0$.

Question 4

Statements: (I) Colligative properties depend on the number of particles. (II) Osmotic pressure is $\Pi = CRT$. Which are correct?

Solution: Both statements are correct.

Question 5

The ideal van't Hoff factor of NaCl is:

Solution: $\text{Na}^+ + \text{Cl}^-$ = 2 particles.

Question 6

Adding antifreeze to a radiator works by:

Solution: Antifreeze lowers the freezing point of water.

Question 7

A solution showing positive deviation forms:

Solution: Positive deviation gives minimum-boiling azeotropes.

Question 8

For benzoic acid dimerising in benzene, the colligative effect is:

Solution: Association ($i<1$) reduces the colligative effect.

Section B — Assertion & Reason

Question 9

A: Molality is preferred over molarity in colligative-property calculations.
R: Molality does not change with temperature because it is based on the mass of the solvent.

Solution: Temperature independence is exactly why molality is preferred — R explains A.

Question 10

A: An aqueous NaCl solution shows a greater depression of freezing point than an equimolar glucose solution.
R: NaCl dissociates into two ions, giving a van't Hoff factor of about 2.

Solution: More particles ($i\approx2$) means a larger colligative effect — R explains A.

Question 11

A: The vapour pressure of a solvent increases when a non-volatile solute is added.
R: The mole fraction of the solvent in the solution is less than one.

Solution: Vapour pressure actually decreases (A false); the solvent mole fraction is indeed less than one (R true).

Question 12

A: Osmotic pressure is the preferred colligative property for measuring the molar mass of macromolecules.
R: Osmotic pressure can be measured accurately at room temperature even for dilute solutions.

Solution: Its accurate room-temperature measurement is why it suits macromolecules — R explains A.