English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

Which of the following represents the solubility of sugar in water at 20°C ?

Which of the following represents the solubility of sugar in water at 20°C ?

Which one of the following is not a chemical change ?

Which one of the following is not a chemical change ?

One of the following liquids will leave behind a residue on heating. This one is :

One of the following liquids will leave behind a residue on heating. This one is :

Which of the following can be called a suspension ?

Which of the following can be called a suspension ?

What is the difference between colloids and suspensions ?

What is the difference between colloids and suspensions ?

One of the following represents the solution of solid in a solid. This one is :

One of the following represents the solution of solid in a solid. This one is :

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

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 ?