Question

Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a :

• A. a physical change that can be reversed.
• B. the chemical change that can be reversed.
• C. a physical change that cannot be reversed.
• D. the chemical change that cannot be reversed.

Answer 1

The correct option is A

a physical change that can be reversed.

The correct option is (A):

Explanation for the correct answer:

A physical change that can be reversed:

1. It is actually a change in which the matter will not change the chemical properties of the matter.
2. So, on dissolving the sugar in the hot water there would be a formation of the concentrated hot syrup.
3. Hence, this is a physical change as the new substance formed which is the concentrated sugar syrup will not have the different chemical composition and the properties
4. In this process only the state of the substance is changed, but not the chemical identity.
5. Also this sugar can be separated back by the process known as crystallization.
6. This crystallization is actually a process or the separation technique for solid-liquid, where the mass transfer of the solute from the liquid solution to a pure solid.
7. This crystallization is basically a serial process, through which the sugar can be separated in the crystal form.

Explanation for the incorrect answers:

Option (B):

The chemical change that can be reversed:

1. This chemical change is basically a change in which there is the formation of new substance whose chemical property and the composition would be different.
2. But, on dissolving the sugar in the hot water there would be a formation of the concentrated hot syrup in which there will not be any chemical change of the composition as well as properties.
3. In this, only the state of substance is changed so it is a physical change.
4. But yes, sugar can be reversed through the process of crystallization which is actually a technique where the mass transfer of the solute from the liquid solution to a pure solid..
5. Hence, this option is incorrect.

Option (C):

A physical change that cannot be reversed:

1. It is actually a change in which the matter will not change the chemical properties of the matter.
2. So, on dissolving the sugar in the hot water there would be a formation of the concentrated hot syrup.
3. Hence, this is a physical change as the new substance formed which is the concentrated sugar syrup will not have the different chemical composition and the properties
4. In this process only the state of the substance is changed, but not the chemical identity.
5. But the sugar can be reversed back by the process of crystallization.
6. Hence, this option is incorrect.

Option (D):

The chemical change that cannot be reversed:

1. This chemical change is basically a change in which there is the formation of new substance whose chemical property and the composition would be different.
2. But, on dissolving the sugar in the hot water there would be a formation of the concentrated hot syrup in which there will not be any chemical change of the composition as well as properties.
3. In this, only the state of substance is changed so it is a physical change.
4. But the sugar can be reversed back by the process of crystallization.
5. Hence, this option is incorrect.

Therefore, the correct option is (A): a physical change that can be reversed.