Disadvantages of synthetic fibres are :
(i) It melts on heating.
(ii) Its clothes catch fire easily
(iii) It melts and sticks to the body of the person wearing it, when it is heated.

Rayon is made from cellulose obtained from wood pulp. Nylon, polyester and acrylic are made entirely of chemicals. Nylon, polyester are made up of repeating units of amides and esters respectively

Properties of nylon are:
(i) Nylon is a synthetic fibrous material that is known for its high tensile strength, abrasion resistance and chemical stability.
(ii) It is a very resilient fibre that is often used to make cords and ropes that need to support a lot of weight and withstand in wet, hot or dirty condition.
(iii) When used in clothing, nylon is both light weight and warm.

Rayon is a synthetic fibre having properties similar to that of silk. It was obtained by chemical treatment of wood pulp. That is why, it is called an artificial silk.

Examples are given below shows that plastics are non-corrosive in nature:
(i) They do not react with any substance. That is why, they are used to store various kinds of materials and chemicals.
(ii) Plastics do not react with air and water, so it will not show corrosion

(i) Shruti was aware that plastic is a non-biodegradable material. Disposal of plastic is a major problem. It is not easily decomposed by natural process. So, to avoid the use of plastic she prefers to take steel lunch box.
(ii) No, plastic materials are not environment friendly since, they take several years to decompose and cause environmental pollution. Besides, in the burning process, it releases lots of poisonous fumes (gases) into the atmosphere causing air pollution.
(iii) Shruti is very aware, sensible and intelligent girl.

Plastic is non-biodegradable and causes environmental pollution as it takes several years to decompose. It is not environment friendly. When the plastic waste materials are burnt, they burn very slow. They do not get completely burnt. In the burning process, they release lots of poisonous fumes (gases) into the atmosphere causing air pollution. The animals eat up the polythene bags and wrappers of food along with the leftover food thrown on garbage dumps.
The methods to limit its consumption are:
Reducing its use; reusing it for some other purposes and recycling. It may reduce environmental pollution also.

Plastic is non-biodegradable substance, so it cannot be decomposed. It is creating a great problem for environment. While burning it gives lots of poisonous gases and takes a long time to degrade. This pollution is a major threat to our environment.
(i) Polythene bags are also a big threat to our environment.
They are non-biodegradable substances. When people throw peels of vegetables and left over food items in plastic bags they are eaten by animals such as cows. The plastic material chokes the respiratory system of these animals or forms a lining in their stomach and can be the cause of their death.
(ii) The polybags carelessly thrown here and there are responsible for clogging the drains. Carelessly the wrappers of chips, biscuits etc. are thrown here and there on picnic spots and roads which all create pollution in our environment.
(iii) Plastic wast, when dumped in water,r causes water pollution. Aquatic animals consume these plastics and die.
Hence, the plastics are not environment friendly.

(a) Nikita was aware that plastic is a non-biodegradable material. Disposal of plastic is a major problem. It is not easily decomposed by natural process. So, to avoid the use of plastic she prefer to take steel lunch box.
(b) No, plastic materials are not environment friendly since, it takes several years to decompose and causes environmental pollution. Besides, in the burning process it releases lots of poisonous fumes (gases) into the atmosphere causing air pollution.
(c) Nikita is very aware, sensible and intelligent girl.

The importance of synthetic polymers in our life are as follows:
(i) Nylon It is used for making ropes for rock climbing, fishing nets, raincoats, parachutes and tyre cords, etc.
(ii) Acrylic It is used for sweaters, track suits, linings for boots and gloves and in furnishing fabrics and carpets.
(iii) Terylene It is used in textile industry to make clothes like sarees, tapestry and dress material. It is also mixed with natural fibre like cotton and wool to make more variety of clothes.
(iv) Plastics It is used to store food item, water, milk, pickles, dry food, etc. This is because of light weight, low price, good strength and easy handling as compared to metals. Plastics are used in cars, aircrafts and spacecrafts.