Question

All the changes around us are classified as physical and chemical changes.
The changes which undergo change in shape, size or state are called physical changes.
The changes which involve the formation of a new substance are called chemical changes.
Chemical changes are very useful to as.
Rust is a reddish brown substance that appears on the surface of iron articles when they are left exposed to moist air.
Many different types of salts dissolve in water to form solutions.
EXERCISE
Section-
Tick() the correct answer:
1. Which of the following is a chemical change?
(a) Melting of ice-cream
(b) Ironing of clothes
(c) Burning of petrol
(d) Drying of hair
Which of these cannot prevent rusting of iron?
(a) Galvanisation (b) Alloying
(c) Dipping in water
3. The gas produced when zinc reacts with dilute hydrochloric acid is
(a) carbon dioxide (b) hydrogen (c) oxygen
2.
(d) Greasing
(d) none of these​

Answer 1

Answer:

Q1c)Burning of Petrol

Q2Dipping in water

Q3Hydrogen gas

please mark as brainliest

Answer 2

Answer:

1

c) Burning of Petrol

2.c) Dipping in Water

3b) Hydrogen

Explanation:

1) Burning of Petrol causes formation of a new substance & causes a residue. Makes a change in Chemical Composition

2) Dipping of Iron in Water increases the rusting process as it is exposed to more Water, Rusting happens due to reaction of iron with Atmospheric air & water.\

3) In this Reaction, Zinc Chloride (Zn-Cl) is produces with liberation of Hydrogen Gas.