All questions of Separation of Substances for Class 6 Exam

If saturated solution is heated the solution become unsaturated because solubility is directly depends upon temperature, so on heating solubility of the solution increase and its become unsaturated or in other words the solution is now capable to take some more solute into it.

This method of separating components of a mixture is calledwinnowing. Winnowing is used to separate heavier and lighter components of a mixture by wind or by blowing air. threshing is done with the help of bullocks. Ans is B

A solution that has reached the maximum solubility is called a saturated solution . It means you can no longer add solute to the solution . Saturated solution are required for the process of crystallization.

D.pure solution

You should add ice after dissolving the sugar to dissolve more sugar in lemonade. When sugar is dissolved in warm water, it dissolves more readily due to higher solubility at warmer temperatures. Adding ice before dissolving sugar can reduce the temperature of the mixture, making it harder for the sugar to dissolve. Therefore, it is best to dissolve the sugar in warm or room-temperature water first and then add ice to cool the lemonade. This approach ensures that the maximum amount of sugar is dissolved.

Explanation:

To separate a mixture of sugar and water, the most effective method is evaporation. Here's how it works:

Evaporation:
Evaporation is a process where a liquid changes into its gaseous state. In the case of a sugar-water mixture, the water evaporates, leaving behind the sugar.

1. Heating the mixture: The sugar-water mixture is heated gently. As heat is applied, the water molecules gain energy and begin to move faster. This increased kinetic energy allows the water molecules to escape from the liquid and enter the air as water vapor.

2. Evaporation: As the water evaporates, it separates from the sugar molecules. The sugar molecules are too large to evaporate and remain in the container.

3. Condensation: The water vapor rises and cools down in the air. It then condenses back into liquid water when it comes into contact with a cooler surface, such as the walls of the container or a condenser.

4. Collection: The condensed water droplets are collected, leaving behind the sugar in the original container.

Advantages of Evaporation:
- Evaporation is a simple and cost-effective method to separate sugar and water.
- It does not require any special equipment, making it suitable for everyday use.
- The separated components can be easily collected and used further if desired.

Other Methods:
The other options mentioned in the question are not suitable for separating a sugar-water mixture:

- Filtration: Filtration is used to separate solid particles from a liquid or gas by passing it through a filter. However, in the case of sugar and water, the sugar particles are too small to be effectively filtered, making this method ineffective.

- Separating Funnel: A separating funnel is used to separate immiscible liquids with different densities. It is not suitable for separating sugar and water, as they form a homogeneous mixture with the sugar dissolved in the water.

- Decantation: Decantation is the process of separating a liquid from solid particles by carefully pouring off the liquid, leaving the solid behind. However, in the case of a sugar-water mixture, the sugar is dissolved in the water and cannot be separated by decantation.

Therefore, the correct answer is evaporation for separating a mixture of sugar and water.

Sieving is the method used to separate sugar from wheat flour. Since sugar and flour have different particle sizes, a sieve with appropriate mesh can separate them. This method is commonly used in cooking and baking to ensure that flour and sugar are evenly mixed or to remove lumps from the ingredients.

Explanation:

Methods of Separating Substances from Mixtures:

Handpicking:
- Involves manually picking out components of a mixture based on their physical properties.
- Useful for separating larger particles from a mixture.

Winnowing:
- Involves blowing air through a mixture to remove lighter components.
- Effective for separating grains from chaff or dirt.

Sieving:
- Involves passing a mixture through a sieve or mesh to separate particles based on size.
- Useful for separating solids of different sizes.

Sedimentation:
- Involves allowing particles to settle at the bottom of a container due to gravity.
- Useful for separating insoluble solids from liquids.

Decantation:
- Involves pouring off the liquid portion of a mixture while leaving the solid behind.
- Useful for separating liquids with different densities.

Filtration:
- Involves passing a mixture through a filter to separate solid particles from a liquid.
- Useful for separating insoluble solids from liquids.
These methods are essential in chemistry and everyday life for separating different substances from mixtures based on their physical properties.

Introduction:
Mixtures are combinations of two or more substances that are physically mixed together but can be separated through various methods. The need to separate mixtures arises due to several reasons, including the removal of undesirable substances, obtaining desirable substances, and obtaining highly pure substances. Consequently, the correct answer to the given question is option 'D', which encompasses all of the above reasons.

Explanation:
1. Removal of Undesirable Substances:
One of the primary reasons for separating mixtures is to remove undesirable substances. In many cases, mixtures contain impurities or unwanted components that need to be eliminated in order to obtain a desired product or to make the mixture safe for consumption. Separation techniques such as filtration, distillation, and chromatography are commonly employed for this purpose.

- Filtration: Filtration is used to separate a solid-liquid mixture, where the solid particles are larger than the pores of the filter paper or mesh, allowing only the liquid to pass through.
- Distillation: Distillation is used to separate a mixture of two or more liquids with different boiling points. The mixture is heated, and the component with the lower boiling point vaporizes first and can be collected separately.
- Chromatography: Chromatography is a technique that is used to separate a mixture into its individual components based on their different affinities to a mobile phase and a stationary phase.

2. Obtaining Desirable Substances:
Separating mixtures is also essential for obtaining desirable substances. Sometimes, mixtures contain valuable or useful substances that need to be isolated for further processing or utilization. By employing suitable separation methods, these substances can be obtained in their pure form.

- Evaporation: Evaporation is used to separate a mixture of a solid dissolved in a liquid. The mixture is heated, and the liquid component evaporates, leaving behind the solid residue.
- Crystallization: Crystallization is a technique used to separate a solid dissolved in a liquid by cooling the mixture. The dissolved solid forms crystals, which can be separated from the liquid.
- Sublimation: Sublimation is the process of separating a mixture where one component undergoes sublimation, i.e., it changes directly from a solid to a gaseous state without passing through the liquid phase. The sublimed substance can be collected separately.

3. Obtaining Highly Pure Substances:
Separating mixtures is also essential to obtain highly pure substances. In many scientific and industrial applications, it is necessary to isolate individual components of a mixture with a high degree of purity. This can be achieved through various separation techniques.

- Centrifugation: Centrifugation is used to separate mixtures based on the differences in density or particle size. The mixture is spun rapidly, causing the denser or larger particles to settle at the bottom, while the lighter or smaller particles remain in the liquid or on top.
- Decantation: Decantation is a simple method used to separate a mixture of a solid settled at the bottom of a container and a liquid. The liquid is carefully poured off, leaving the solid behind.
- Electrolysis: Electro