MCQ on Solutions: Introduction and Explanation

Ans: c. Sugar in Water

Explanation: A mixture having same compounds in same proportions is known as a Homogeneous Mixture. If the proportions of the compounds are different in a mixture then it is called as a Heterogeneous Mixture. In sugar water solution, the compounds are even throughout the mixture. There are no clear boundaries of separation in the sugar in water mixture.

Ans: d. Both tap and sea water

Explanation: Tap and Sea water consists of impurities which makes them good conductor of electricity. Tap water consists of many other types of ions and minerals that can conduct electricity. Likewise, Sea water contains ions that can conduct electricity making it a good conductor of electricity. Pure water is a poor conductor of electricity as no impurities are present in it. Some examples of Good conductors of electricity are Graphite, Silver, Copper, etc, and hence, can be used to make conducting wires. Whereas, Plastic, Pure Water, Diamond, Wood, etc, are poor or bad conductors of electricity due to which they are used in the manufacturing of insulating covers, switches, etc.

Ans: d. The boiling point of the water increases

Explanation: Due to the presence of salt in the water, the boiling point of this solution increases than that of the pure water. As the ionic bond in salt is weaker than the covalent bond of water, salt gets dissolved in the water and results in the presence of Na+ and Cl- ions in the solution. The dissociated ions of NaCl gets surrounded by the positive and negative charged sides of the water molecule which affects the intermolecular attraction in the molecules of the water. Hence, to change from liquid to vapor phase, the amount of energy required increases.

Ans: b Hypertonic solution

Explanation: The solute concentration of a hypertonic solution is high, and when a plant or an animal cell is placed in this solution, the cell shrinks. The water present in the cell moves outwards causing the cell to shrink as it loses water. Whereas, when the cell is kept in a hypotonic solution, the cell will swell as the water will move from the solution and will enter in the cell. The movement of the solvent towards a higher concentration of solute is known as Osmosis. 

Ans: d. increasing the number of solute molecules

Explanation: The solute particles’ molar concentration and osmotic pressure of a solution are directly proportional to each other. 

πV=nRT

When the solute molecules increases, the osmotic pressure of the solution also increases. 

Ans: b. ppm

Explanation: The atmospheric pollution is measured in ppm (parts per million) as the amount of pollutants that are present in the atmosphere is very small. Atmospheric pollution is caused due to the presence of certain gases alongwith the liquid and solid particles that are suspended in the air. There are 6 gases that are majorly responsible for the poor air quality and causes atmospheric pollution which includes gases like lead, sulfur oxides, carbon monoxide, ground-level ozone, particulate matter and nitrogen oxides. 

Ans: c Mercury

Explanation: Atoms of mercury have a strong bond because of which it exerts low vapour pressure. Between the individual atom of mercury, the force of interaction is stronger. Whereas in case of alcohol, the cohesive molecular forces holds several molecules together, such as hydrogen bonding in a molecule.

Ans: d. Raoult’s law

Explanation: According to the Raoult’s law, 

P_solution ∝ X_solvent

The partial pressure of each component in any solution is directly proportional to the mole fraction in that solution. 

Ans: a. By increasing the number of solute molecules

Explanation: On increasing the number of solute molecules of a solution, the osmotic pressure also increases. Osmotic pressure of a solution depends on original concentration of a solution and the temperature. The osmotic pressure can be increased either by decreasing the amount of the solvent or by increasing the amount of the solute.

Ans: b. 2,3

Explantion: The Tyndall effect of the colloidal particles is shown when they scatter the light and the random movement of the colloidal particles show Brownian Movement. The colloidal particles are so small in size that they can not be seen by the naked eye but when a light is directed towards these particles, it gets scattered. The colloidal particles show zig-zag or random movements due to the continuous bombardment of molecules of Dispersion medium.