Question

D. Choose the correct option
1. Which of the following is not a reversible change?
(a) The changing of water into steam
b) The melting of iron
fe) The burning of kerosene
(d) The freezing of water
2. Which of the following is a reversible change?
(a) The burning of wax
(b) The melting of wax
c) The curdling of milk
(d) The cooking of food
3. During which of the following changes are new substances formed?
(a) Melting
(b) Sublimation
fel Evaporation
(d) Rusting
4. Rusting takes place in
(a) air-free moisture
(b) moisture-free air
ich moist air
id) none of these
5. In which of the following processes is light absorbed?
(a) Sublimation
(b) Burning
Ic Rusting
(d) Photosynthesis​

Answer 1

Answer:

1.b)melting of iron

2.b)the melting of wax

3.d)rusting

4.d)none of these

5.b)burning

Hope these answers are correct and helpful

i am not sure with these answer so please check it

Answer 2

Required Answers:

1) The Burning of Kerosene ($\red{\bf{C}}$)

• Kerosene is a fossil fuel and when it heated, a lot of heat energy is liberated and Carbon dioxide is also evolved as a result. New products are made with entirely different composition. Hence, this can't be reversed.

2) The melting of wax ($\red{\bf{B}}$)

• Here, Melting is a interconversion of state of wax which is due to the heat supplied to the solid wax. This process can be reversed by cooling or taking away heat from the melted wax.

3) Rusting ($\red{\bf{D}}$)

• Rusting is a chemical process due to the result of Iron reacting with Water vapour, Oxygen in the atmosphere. This harms the Iron and makes it weak. This can be prevented by Galvanising or Painting the metal.

4) Moist Air ($\red{\bf{C}}$)

• Rusting is an application of oxidation in the nature. Here, Iron metal when exposed to moist air(that contains water and oxygen) changes to form Ferric oxide which gives it a reddish brown appearance.

5) Photosynthesis ($\red{\bf{D}}$)

• It is the process of making food by the plants with the helps of raw materials like Carbon dioxide, Water in ten presence of Sunlight and Chlorophyll. The light energy is trapped by the green pigment, Chlorophyll found in the palisade cells of leaves.

━━━━━━━━━━━━━━━━━━━━