Question

Give one example each of a chemical reaction showing the following different

characteristics.

a. evolution of gas

b. formation of precipitate

c. change of state from gas to liquid​

Answer 1

Answer :

1. Evolution of gas

When zinc reacts with dilute sulphuric acid hydrogen gas is evolved with effervescence.

Zinc + Dilute sulphuric acid ➝ Zinc sulphate + Hydrogen

$\sf{Zn+{H}_{2}{SO}_{4} \longrightarrow \: {ZnSO}_{4}+{H}_{2} \uparrow}$

2. Formation of precipitate

When dilute sulphuric acid is added to the solution of barium chloride a precipitate of barium sulphate is formed.

Barium chloride + Dilute sulphuric acid ➝ Barium sulphate + HCl

$\sf{Ba{Cl}_{2}+{H}_{2}{SO}_{4} \longrightarrow \: {BaSO}_{4} \downarrow\: 2HCl}$

3. Change of state from gas to liquid

In this reaction, hydrogen and Oxygen gas reacts and forms water.

Hydrogen + Oxygen ➝ Water

$\sf{{2H}_{2}+{O}_{2} \longrightarrow {2H}_{2}O}$

More Information

Evolution of gas is represented by an upwardly-directed arrow.

Forming of precipitate is represented by an downwardly-directed arrow.