Liquids

5 free MDCAT Chemistry MCQs on Liquids (PM&DC syllabus), each with the answer, an explanation and the textbook line it comes from. Tap to check, no sign-up.

Tap an answer to check it · 5 questions

1. Question 1

   Hydrogen bonding is NOT involved in:
   • ALiquid methane
   • BLiquid water
   • CLiquid HF
   • DDNA structure
   Show answer and explanation

   Answer: A) Liquid methane

   Methane has only weak (London) forces, hence its very low boiling point (-164 C). Source: Chemistry 11 KPK (taleem360.com), p. 172.

2. Question 2

   Liquids diffuse much more slowly than gases because of:
   • ANo molecular motion
   • BHigh kinetic energy of molecules
   • CAttractions and little empty space
   • DLarge empty spaces between molecules
   Show answer and explanation

   Answer: C) Attractions and little empty space

   Liquid molecules move, but strong attractions and little free space slow their mixing. Source: Chemistry 11 KPK (taleem360.com), p. 156.

3. Question 3

   n-Butane and 2-methylpropane are both C4H10, but n-butane has the higher boiling point because:
   • AStraight chains have stronger London forces
   • BBranched chains have more electrons
   • CIsobutane forms hydrogen bonds
   • Dn-Butane has a higher molar mass
   Show answer and explanation

   Answer: A) Straight chains have stronger London forces

   Same electrons and mass; the straight chain has more surface contact, so stronger dispersion forces. Source: Chemistry 11 KPK (taleem360.com), p. 164.

4. Question 4

   The rate of evaporation of a liquid depends on surface area, temperature and the:
   • AColour of the liquid
   • BStrength of intermolecular forces
   • CShape of the container
   • DTotal volume of liquid
   Show answer and explanation

   Answer: B) Strength of intermolecular forces

   Weaker intermolecular forces let molecules escape more easily. Source: Chemistry 11 KPK (taleem360.com), p. 165.

5. Question 5

   Detergents improve the cleaning action of water because they:
   • ARaise surface tension
   • BReduce surface tension
   • CIncrease hydrogen bonding
   • DRaise boiling point
   Show answer and explanation

   Answer: B) Reduce surface tension

   By breaking hydrogen bonding they lower surface tension, so water wets fabrics easily. Source: Chemistry 11 KPK (taleem360.com), p. 170.

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