Question

give one example of a chemical reaction showing the characteristic in the diagram
A test tube

Answer 1

Answer:

There are several types of chemical reactions: Synthesis, decomposition, single replacement, double-replacement, combustion and acid-base. Interestingly, most of these reactions (with the exception of most double replacement and acid-base) are oxidation-reduction (redox) reactions.

Answer 2

1.Evolution of gas:

The chemical reaction between zinc and dilute sulphuric acid is characterized by the evolution of hydrogen gas.

Zn(s)+H

2

SO4(aq)→ZnSO

4

(aq)+H

2

(g)

2.Change in colour:

The reaction between the lead nitrate solution and potassium iodide solution.

Pb(NO

3

)

2

(aq)+2KI→PbI

2

(s)+2KNO

3

(aq)

In this reaction colour changes from colourless to yellow.

3.Formation of precipitate:

The action of Barium Chloride on sodium sulphate.

BaCl

2

(aq)+Na

2

SO

4

(aq)→BaSO

4

(s)+2KNaCl(aq)

4.Change in temperature:

The action of dilute sulphuric acid on zinc:

Zn(s)+H

2

SO

4

(aq)→ZnSO

4

(s)+H

2

(g)

In this reaction, heat is evolved.

5.Change in the state:

When the wax is burnt in the form of the wax candle then water and carbon dioxide are formed. Wax is solid, water is a liquid whereas carbon dioxide is a gas