Physical and Chemical Changes

One of the following is not a chemical change. This one is

• Ripening of bananas

• Souring of milk

• Decaying of jute bag

• Drying of cotton cloth

Pure salt can be obtained from sea water by the process of:

• neutralization

• boiling

• evaporation

• evaporation and crystallization

Identify the correct statement.

• Rusting and burning are reversible changes

• Physical change is always an irreversible change

• Cutting of apple is an irreversible chemical change

• Beating of egg is a reversible change

A chemical reaction in which magnesium ribbon burns can be represented as

• Magnesium + Oxygen ---> Magnesium oxide

• Magnesium + Oxygen ---> Magnesium hydroxide

• Magnesium + Water ---> Magnesium hydroxide

• Magnesium + Oxygen + Water---> Magnesium hydroxide

A solution in which no more solute can be dissolved at a particular temperature is called:

• Saturated solution

• Unsaturated solution

• Sugar solution

• Impure solution

Iron gate if not painted gets rusted due to the presence of mosture and air

• True

• False

Mark the correct statement.

• Hydrogen gas is evolved when vinegar is added to baking soda

• Heat energy is always given out during a chemical change

• New product is always formed during a chemical change

• Combining of two substances by heating is a physical change.

Which of the following is an example of a reversible change?

• Freezing of water

• Burning of paper

• Rusting of iron

• Decomposition of food

Melting of wax is

• an irreversible physical change

• an irreversible chemical change

• a reversible chemical change

• a reversible physical change

Galvanization is the process in which

• iron is coated on zinc metal

• zinc and iron are mixed in molten state

• zinc is coated as a layer on iron

• carbon is mixed with iron and heated