Tag: chemistry

Solution:- (B) ${d} _{xy}, {d} _{yz}$

The green-coloured $ Cr _2O _3$ powder is blown in the air by the large volume of $ N _2$ and water vapour produced and settles like dust from the volcano. 

$Sc^{3+}$ has electron configuration of [Ar] $4s^0  3d^0$. Therefore without any unpaired electrons it forms a colorless solution in aqueous medium. 

Acrylic fibers are synthetic fibers made from a polymer (polyacrylonitrile) with an average molecular weight of $\sim100,000$, about $1900$ monomer units. Strong and warm, acrylic fiber is often used for sweaters and tracksuits and as linings for boots and gloves, as well as in furnishing fabrics and carpets. It is manufactured as a filament, then cut into short staple lengths similar to wool hairs, and spun into yarn.
option A is correct

After people began to settle in agricultural communities, they learnt to weave twigs and grass into mats and baskets. Vines, animal fleece or hair were twisted together into long strands. These were woven into fabrics.

In ancient times, barks and big leaves of trees or animal skins and furs were used by people to cover themselves.

Stitched clothes have gone through many variations since the invention of stitching. But, even today, saree, dhoti, lungi or turban is used as an un-stitched piece of fabric.

After people began to settle in agricultural communities, they learnt to weave grass and twigs into mats and baskets.

Egypt is known as the oldest agricultural civilization. Due to less rainfall, river Nile was used as a source of water for agriculture. Hence, in ancient Egypt, cotton as well as flax were cultivated near the river Nile and were used for making fabrics.

With the invention of the sewing needle people started stitching fabrics to make clothes.