Answer: a. ![H_2AsO_4^{-}(aq)+H_2O(l)\rightarrow HAsO_4^{2-}(aq)+H_3O^+(aq)](https://tex.z-dn.net/?f=H_2AsO_4%5E%7B-%7D%28aq%29%2BH_2O%28l%29%5Crightarrow%20HAsO_4%5E%7B2-%7D%28aq%29%2BH_3O%5E%2B%28aq%29)
b. ![K_a=\frac{[HAsO_4^{2-}]\times [H_3O^+]}{[H_2AsO_4^{-}]}](https://tex.z-dn.net/?f=K_a%3D%5Cfrac%7B%5BHAsO_4%5E%7B2-%7D%5D%5Ctimes%20%5BH_3O%5E%2B%5D%7D%7B%5BH_2AsO_4%5E%7B-%7D%5D%7D)
Explanation:-
According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.
The balanced chemical equation is:
![H_2AsO_4^{-}(aq)+H_2O(l)\rightarrow HAsO_4^{2-}(aq)+H_3O^+(aq)](https://tex.z-dn.net/?f=H_2AsO_4%5E%7B-%7D%28aq%29%2BH_2O%28l%29%5Crightarrow%20HAsO_4%5E%7B2-%7D%28aq%29%2BH_3O%5E%2B%28aq%29)
Here,
is loosing a proton, thus it is considered as an acid and after losing a proton, it forms
which is a conjugate base.
And,
is gaining a proton, thus it is considered as a base and after gaining a proton, it forms
which is a conjugate acid.
The dissociation constant is given by:
![K_a=\frac{[HAsO_4^{2-}]\times [H_3O^+]}{[H_2AsO_4^-]}](https://tex.z-dn.net/?f=K_a%3D%5Cfrac%7B%5BHAsO_4%5E%7B2-%7D%5D%5Ctimes%20%5BH_3O%5E%2B%5D%7D%7B%5BH_2AsO_4%5E-%5D%7D)
Answer 1) : The phosphorus minerals deposits that are currently available is not enough for the future, and the distribution of the ores are also uneven throughout the globe. The major part of food production are also dependent on the production of phosphorus. Phosphorus is also widely used as fertilizer and most of the population of farmers are dependent on it. This has increased the need to preserve and save the phosphorus.
Answer 2) : To measure the current availability of phosphorus found in plants of thermally conditioned sewage sludge, phosphorus radiotracer technique was used and the present amount of phosphorus was determined. A study of experiment in ryegrass was done in pots whcih were filled with soil that underwent isotopic P-labelling, and no fertilizer was added, thermally conditioned sewage sludge as fertilizer. Then shoot and roots were harvested at definite fixed intervals, and their radioactivity was analyzed to measure phosphorus uptake.
Answer 3) : Although there is no major disadvantage of using thermally conditioned sewage sludge as a fertilizer but they incur a great cost on their maintenance and operation, along with this they produce strong odors which is not possible to get rid off, they also generate large amount of liquor waste; handling and safe disposal of that is quite difficult. Continuous physical conditioning has to be given.
Answer: H₂SO₄ is the chemical formula that represents sulfuric acid.
Explanation:
1) H stands for hydrogen and H₂ means that each unit contains two atoms of hydrogen.
2) S stands for sulfur. Since there is not subscript, means each unit contains one atom of sulfur.
3) O stands for oxygen, and O₄ means that each unit has four oxygen atoms.
4) The way the compound is build up is the S atom at the center with two double bonds to each to one atom of O, and two single bonds one to each OH ion.
5) Sulfuric acid is a strong acid, so it dissociates in water and alghough the formula H₂SO₄ is used to represent it, the aqueous solution is formed by ions: HSO₃⁻, H⁺, SO₄²⁻, and OH⁻, as represented by these dissociation equaitons show:
1) H₂SO₄ ⇄H⁺ + HSO₄⁻ first dissociation
2) HSO₄⁻ ⇄ H⁺ + SO₄²⁻ second dissociation
So, H₂SO₄ is one form to represent sulfuric acid.
False.
Stoichiometry is also used to make other calculations: limitant or excess reagents and quantity of products produced are two important uses of stoichiometry. Furthermore it is used to make energy calculations related with the chemical reactions.