Answer:
The correct answer is :
Natural fibres: these fibers are found naturally in the environment such as cotton, hemp or wool, all are made naturally found fibers.
sr. no. name type
1 Cotton natural
2 Linen natural
3 Silk natural
4 Wool natural
5. Hemp natural
Artificial fibres: made from the polymerization of their monomer unit for example polyester made from coal and petroleum products.
sr. no. name type
1 Polyester artificial
2 Rayon artificial
3 Spandex artificial
4 Acrylic artificial
5. microfibers artificial
Sound travels most quickly through solids because _____.
answer is: because solids r the most sense.
The distance between molecules in solids r very small.Because they are so close, they can collide very quickly, i.e. it takes less time for a molecule of the solid to 'bump' into its neighbor. Solids are packed together tighter than liquids and gases, hence sound travels fastest in solids.
Answer: (A)
(B) 
Explanation:
(A) As we know that HCl is a strong acid and when it is added to an aqueous solution then it leads to increase in the concentration of hydrogen ions. And, when an acid or base is added to a solution then any resistance by the solution in changing the pH of the solution is known as a buffer.
This means that addition of buffer into the given solution will not cause much change in the concentration of
in large amount.
As both the buffer components are salt then they will remain dissociated as follows.
Hence, net ionic equation will be as follows.
(B) When we add small amount of sodium hydroxide into the solution then there will occur an increase in concentration of hydroxide ions into the solution. But then due to the presence of buffer there will occur not much change in concentration and the acid will get converted into salt.
The net ionic equation is as follows.

Correct answer is
.
Phosphoric acid is a polyprotic acid having 3 acidic hyrdogen therefore it will have 3 pka values.
The equations for the release of acidic hydrogen can be written as:

From the pka values we can judge the idea of pH as using Henderson-Hasselbalch Equation, we get the relation between pH and pka.

Using the following equation, relation of pH and pka is
![pH=pka+log\frac{[A^-]}{HA}](https://tex.z-dn.net/?f=pH%3Dpka%2Blog%5Cfrac%7B%5BA%5E-%5D%7D%7BHA%7D)
Using this equation, we can find that the equation having pka= 2. 14 is closest to the pH=3.2 so the ionic form in this equation will be dominant at the same pH.
Therefore at pH=3.2 the ionic form
of
is dominant.