English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

Tincture of iodine has antiseptic properties. This solution is made by dissolving :

When the solid A is added to water, it dissolves with the evolution of a lot of heat and making little explosions to form two products B and C. The properties of products B and C are entirely different from those of solid A as well as water. Moreover, products B and C cannot be reconverted into solid A and water. When another solid D is added to water, it dissolves with the absorption of a little heat to form a product E which cools down. The product E shows the properties of both, solid D as well as water. Moreover, product E can be converted into solid D and water.

(a) What type of change occurs when solid A is dissolved in water ? Why ?

(b) What type of change occurs when solid D is dissolved in water ? Why ?

(c) Name a metal which you think could behave like solid A. Also name the products B and C.

(d) Name the solid D if it is the one which is used in making ordinary dry cells.

(e) Name the process by which D can be recovered from E.

When the solid A is added to water, it dissolves with the evolution of a lot of heat and making little explosions to form two products B and C. The properties of products B and C are entirely different from those of solid A as well as water. Moreover, products B and C cannot be reconverted into solid A and water. When another solid D is added to water, it dissolves with the absorption of a little heat to form a product E which cools down. The product E shows the properties of both, solid D as well as water. Moreover, product E can be converted into solid D and water.

(a) What type of change occurs when solid A is dissolved in water ? Why ?

(b) What type of change occurs when solid D is dissolved in water ? Why ?

(c) Name a metal which you think could behave like solid A. Also name the products B and C.

(d) Name the solid D if it is the one which is used in making ordinary dry cells.

(e) Name the process by which D can be recovered from E.

100 mL of water at room temperature of 25°C is taken in a beaker and a little of solid S is dissolved in it by stirring to obtain a solution X. More and more of solid S is added to the solution with constant stirring, while keeping the temperature of solution constant at 30°C. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker.

1. The contents of beaker are filtered through a filter paper to obtain solution Y in the form of a filtrate.
2. What name is given to solutions like X ?
3. What name is given to solutions like Y ?
4. What will you observe if the solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice ? Why ?
5. What term is used to denote the amount of solid dissolved in 100 grams of water in a solution lie Y ?

100 mL of water at room temperature of 25°C is taken in a beaker and a little of solid S is dissolved in it by stirring to obtain a solution X. More and more of solid S is added to the solution with constant stirring, while keeping the temperature of solution constant at 30°C. After some time it is observed that no more solid dissolves in water and at the same time some solid is also left undissolved at the bottom of the beaker.

1. The contents of beaker are filtered through a filter paper to obtain solution Y in the form of a filtrate.
2. What name is given to solutions like X ?
3. What name is given to solutions like Y ?
4. What will you observe if the solution Y at 30°C is cooled down to 10°C by keeping the beaker in crushed ice ? Why ?
5. What term is used to denote the amount of solid dissolved in 100 grams of water in a solution lie Y ?

The solubility of ammonium chloride in water at various temperatures is given below :

What mass of ammonium chloride would be needed to make a saturated solution of ammonium chloride in fifty grams of water at 40°C ?

The solubility of ammonium chloride in water at various temperatures is given below :

What mass of ammonium chloride would be needed to make a saturated solution of ammonium chloride in fifty grams of water at 40°C ?

What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?

What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?

Name the property of one of the constituents which can be used to separate a mixture of salt and iodine

Name the property of one of the constituents which can be used to separate a mixture of salt and iodine

What difference in the property of two miscible liquids enables their separation by fractional distillation ?

What difference in the property of two miscible liquids enables their separation by fractional distillation ?

State whether the following statement are true or false :

Alcohol can be separated from a mixture of alcohol and water by a separating funnel.

State whether the following statement are true or false :

Alcohol can be separated from a mixture of alcohol and water by a separating funnel.

State whether the following statement are true or false :

Salt and water can be recovered from an aqueous salt solution by the process of evaporation.

State whether the following statement are true or false :

Salt and water can be recovered from an aqueous salt solution by the process of evaporation.

Name the source from which nitrogen and oxygen are obtained on a large scale.

Name the source from which nitrogen and oxygen are obtained on a large scale.

Name the process by which the various gases of the air are separated.