Chemistry 1 Marks Question

Mole fraction is defined as the number of moles of a component divided by total number of moles of all the components present in the solution.

Reverse osmosis: pressure larger than osmotic pressure is applied on the solution side.

Hydrogen bonding.

Azeotropes – Binary mixtures having same composition in liquid and vapour phase and boil at a constant temperature.

It is the excess pressure that must be applied to stop the passage of solvent molecules through a semipermeable membrane into the solution.

Liquid A.

The liquid with 180°C.

The liquid with 140°C.
Explanation:
Apply Raoult's Law of partial vapour pressure and Elevation of boiling point.

A-B interactions are more than those between A-A and B-B.

When the new forces of interaction between the components are stronger than those in the pure components, then non-ideal solutions show negative deviations.

In pure alcohol and water, the molecules are held tightly by a strong hydrogen bonding. The interaction between the molecules of alcohol and water is weaker than alcohol-alcohol and water-water interactions. As a result, when alcohol and water are mixed, the intermolecular interactions become weaker and the molecules can easily escape. This increases the vapour pressure of the solution, which in turn lowers the boiling point of the resulting solution.

It means that the freezing point of water is lowered by 1.86K when 1 mole of non-volatile solute is dissolved in 1kg of water.

A-B interactions are less than A-A and B-B interactions.

Common salt is called de-icing agent as it lowers the freezing point of water to such an extent that it does not freeze to form ice. Thus, it is used to clear snow from roads.

The intermolecular attractive forces between the A-A and B-B are nearly equal to those between A-B.

A-B interactions are weaker than those between A-A or B-B.

Minimum boiling azeotropes are those which boil at lower temperature than boiling point of each component in pure state, e.g., 95.5% ethyl alcohol and 4.5% water by mass.

Insoluble: toluene, chloroform.
Partially soluble: phenol, pentanol.
Highly soluble: formic acid, ethylene glycol.

No, it is a colloidal solution.

Colligative properties are those properties which depend upon the number of moles of solute particle but not on the nature of solute particles.

A-B interactions are more than A-A and B-B interactions.

If the pressure applied on the solution is greater than the osmotic pressure then the solvent molecules start to move from solution into solvent through semipermeable membrane. This process is called reverse osmosis.

Assertion is correct statement but reason is a wrong statement because a semipermeable membrane permits solvent molecules to pass through a solution of lower concentration to that of higher concentration Flow of solvent molecule from solvent side to solution side through semipermeable membrane is called osmosis.

Molal elevation constant is defined as the elevation in boiling point when one mole of non-volatile solute is added to one kilogram of solvent.

The given solid solution is the example of interstitial solid solution.
For eg tungsten carbide, where tungsten atoms are arranged in a face centered cubic pattern with carbon atoms in octahedral holes.

Molality is preferred in studies that involves changes in temperature as in some of the colligative properties of solutions. This is because molality depends on masses of solvent which do not change with temperature.

It is the depression in freezing point when 1 mole of non-volatile solute is dissolved in 1000g of solvent.

Osmotic pressure increases with increase in temperature.

The weight over the lid does not allow the steam to go out. As a result, pressure inside the cooker becomes high. Higher the pressure, higher is the boiling point and faster is the cooking.

Molarity changes with temperature because volume changes with temperature.

Alloys like copper in gold.

Liquids that have similar structures and polarities form ideal solutions.

A substance such as ethylene glycol which is added to water to lower its freezing point is called an antifreeze. It is named so as it delays freezing.

At a given pressure the solubility of oxygen in water increases with decrease in temperature. Presence of more oxygen at lower temperature makes the aquatic species more comfortable in cold water.

Maximum boiling azeotropes are those which boil at higher temperature than boiling point of each component in pure state, e.g., 68% nitric acid and 32% water by mass.

Molarity decreases with increase in temperature as volume of solution increases with increase in temperature.

Ethylene glycol lowers the freezing point of water. Due to this, coolant in radiators will not freeze. Otherwise, radiator will burst due to freezing of coolant (water).