As a diprotic acid, the H₂SeO₃ can ionize by step. First step is H₂SeO₃ =(reversible reaction) H⁺ + HSeO₃⁻. And second step is HSeO₃⁻ =(reversible reaction) H⁺ +SeO₃ ²⁻.
Although the moon's distance from earth varies each month because of its eccentric orbit, the moon's mean distance from Earth is nonetheless increasing at the rate of about 3.8 centimeters (1.5 inches) per year
Explanation:
Relation between pH and concentration of hydrogen ions is as follows.
pH = ![-log [H^{+}]](https://tex.z-dn.net/?f=-log%20%5BH%5E%7B%2B%7D%5D)
So, it means that an increase in the value of pH will show that there occurs a decrease in concentration of hydrogen ions.
Therefore, the solution becomes basic in nature.
On the other hand, a decrease in the value of pH will show that there occurs an increase in the concentration of hydrogen ions.
Therefore, the solution becomes more acidic in nature.
Hence, if the pH of a solution is decreased from pH 8 to pH 6 it means that the concentration of hydrogen ions has increased in the solution.
Answer:
Explanation:
So, the formula for the compound should be:

Now we assume that we have 1 mol of substance, so we can make calculations to know the molar mass of element X, as follows:

So we have that 6 moles weight 212.7g, and we can make a rule of three to know the weight of compound X:

As we used 1 mol, we know that the molar mass is 32.06g/mol
So the element has a molar mass of 32.06 g/mol and an oxidation state of +6, with this information, we can assure that the element X is sulfur, so the compound is 
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Answer:</h2>
The magnesium ribbon, <u>D. It forms a material to cast the tool mark</u>.
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Explanation:</h2>
When a magnesium ribbon is burnt in the presence of oxygen it gives out strong light and heat is produced. Apart from it, it leads to the production of substance called as magnesium oxide which is formed as the product due to the reaction of magnesium with the oxygen present in the air.
Tool marks are the mark which is created by tools while using them. In order to identify or locate them castes made up of magnesium oxide is utilized. When this is pasted on the suspected area, the tool mark of the suspected tool gets pasted on it.