Question

Example of formation of precipitate in chemical reaction

Answer 1

Sometimes when two liquids combine, a solid forms and falls to the bottom of the liquid. This solid is a new substance, called a precipitate, and is evidence that a chemical reaction has occurred. Soap scum, a common example of a precipitate, forms when certain minerals in hard water react with soap molecules.

Answer 2

Answer:

1. Change in colour :

The reaction between lead nitrate solution and poassium iodide solution.

Chemical equation as follow :

Pb ( NO₃ )₂ + 2 KI  ⇒  PbI₂ + 2 KNO₃

In above reaction colour change from colourless to yellow.

2. Change in temperature :

The reaction between dil. sulphuric acid on zinc.

Chemically :

Zn + H₂SO₄  ⇒  ZnSO₄ + H₂

Heat evolved in the above reaction.

3. Formation of precipitation​ :

The reaction between barium chloride on sodium sulphate.

Chemically :

BaCl₂ + Na₂SO₄  ⇒  BaSO₄ + 2 NaCl

In the above reaction white ppt. of BaSO₄ will form.