Question

The excess of silica _______ the cohesion between earth particles.
1. highly increases
2. slowly increases
3. does not affects
4. destroys

Answer 1

Correct Answer - Option 4 : destroys

Explanation:

Ingredients of brick:

Alumina(20-30%):

• Alumina imparts plasticity to the brick so that it can be moulded.
• If alumina present in excess quantity the shrinkage and warping are occurring during the drying process & it becomes too hard during the burning process.

​Silica(50-60%):

• It prevents shrinkage, cracking, and warping of raw bricks and provides uniform shape and size to the bricks.
• If it is in excess quantity it destroys the cohesion between particles.

​Lime(<5%):

• The sand is infusible alone but sand is fuse in the presence of lime.
• If lime is in excess quantity it causes the bricks to melt hence the shape of bricks is loss.

Iron oxide(5-6%):

• Iron oxide imparts red colour to the brick.
• It helps to the fusion of lime and sand.
• The excess quantity imparts dark blue colour and on other hands, the less quantity of iron oxide imparts a yellow colour to the bricks.

Magnesia(1%):

• It imparts a yellow colour and prevents shrinkage.
• If it is in excess quantity it leads to the decay of bricks.