True

Adhesives are the substances used to join the components.

True

Epsom is largely used in medical industries.

Low concentrated phenol is used as a disinfectant.

(i) Cement becomes hardened when it is mixed with water.
(ii) It is necessary to control the rate of hardening.
(iii) so that, Gypsum is added to cement at the final grinding process.

i) In making black board chalks.
ii) In surgery for setting fractured bones.
iii) For making casts for statues and toys etc.
iv) In construction industry.

i) It is a weak acid.
ii) It is a volatile white crystalline powder.
iii) It is colourless. But changes to red in the presence of dust.

i) water loving side
ii) water hating side

water, Sodium hydroxide and coconut oil.

i) Used as fertilizers.
ii) Used in the process of making cement.
iii) In the process of making Plaster of Paris.

Cement is manufactured by crushing of naturally occurring minerals such as lime, clay and gypsum.

(i) Earthworms take organic wastes as food and produce compost castings.
(ii) They improve the soil health and consequently plant health.
(iii) Because of the multitude of services, Earthworms are known as Farmer's friend.

Aim: Soap manufacturing.
Requirements:
i) 35 ml of water.
ii) 10 ml of NaOH.
iii) 60 ml of coconut oil.
Procedure:
i) Cover your work area with old newspaper.
ii) Take 35 ml of water in a jar.
iii) Add 10 gram of concentrated NaOH and allow it to cool.
iv) Then add 60 ml of coconut oil drop by drop and stir it well.
v) On getting dried, soap can be obtained.

Bio waste to compost preparation:
Step (i) : Acquire a bin.
Wooden bins or small pits are taken for the process.
Step (ii) : Prepare the bedding.
Soil or moist news papers are used as a bed.
Step (iii) : Add the worms.
Spread the worms on the bedding with moist newspaper.
Step (iv) : Bury food scraps under bedding.
Feed the worms with fruit and vegetable scraps.
Step (v) : Place a full sheet of dry newspaper on the top of the bedding.
Replace this sheet frequently.
Step (vi) : Choose a cover for the bin.
Cover the bin with a lid for about, 3-4 weeks with proper air contact.
Benefits of Vermi castings:
(i) Adds organic matter to the soil.
(ii) Soil absorbtion and retentivity of water is increased.
(iii) Helps to form soil aggregates.
(iv) Ease cultivation.