Answer:
The wavelength the student should use is 700 nm.
Explanation:
Attached below you can find the diagram I found for this question elsewhere.
Because the idea is to minimize the interference of the Co⁺²(aq) species, we should <u>choose a wavelength in which its absorbance is minimum</u>.
At 400 nm Co⁺²(aq) shows no absorbance, however neither does Cu⁺²(aq). While at 700 nm Co⁺²(aq) shows no absorbance and Cu⁺²(aq) does.
The mass of nitric acid required to make the given solution is 0.0627 g.
The given parameters:
- <em>Volume of the acid, V = 250 mL</em>
- <em>pH of the acid, = 2.4</em>
The hydrogen ion (H⁺) concentration of the nitric acid is calculated as follows;

The molarity of the nitric acid is calculated as follows;

The number of moles of the nitric acid is calculated as follows;

The molar mass of nitric acid is calculated as;

The mass of the nitric acid contained in the calculated number of moles is calculated as;

Thus, the mass of nitric acid required to make the given solution is 0.0627 g.
Learn more about molarity of acids here: brainly.com/question/13864682
Lowest is Hydrogen highest is <span>Beryllium
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If sodium is burned in chlorine fuel, a compound is formed that dissolves in water. the solution be: Bright yellow mild
Chlorine is a yellow-green gas at room temperature. Chlorine has a smelly, annoying scent similar to bleach that is detectable at low concentrations. The density of chlorine gasoline is about 2.5 times extra than air, so one can reason it to initially stay near the floor in regions with little air movement.
Chlorine gasoline can be recognized by using its smelly, anxious smell, which is like the scent of bleach. The sturdy scent may additionally provide a good enough caution to human beings that they have been uncovered. Chlorine fuel appears to be yellow-green in color. Concentrations of approximately 400 ppm and past are commonly fatal over a half-hour, and at 1,000 ppm and above, fatality ensues within only some mins. A spectrum of scientific findings can be present in those uncovered to excessive tiers of chlorine.
Learn more about Chlorine here:
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