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.
It takes so much heat to melt ice or evaporate water because extra energy is required to break the hydrogen bonds between water molecules.
<h3>
Hydrogen bond</h3>
Hydrogen bonding is an electrostatic force of attraction between a hydrogen atom found between a pair of other atoms having a high affinity for electrons.
Hydrogen bonds cause water to be exceptionally attracted to each other creating cohesion.
It takes so much heat to melt ice or evaporate water because extra energy is required to break the hydrogen bonds between water molecules.
Find out more on Hydrogen bond at: brainly.com/question/12798212
Explanation:
Bayer process is industrial method of the refining of the bauxite to produce alumina which is aluminum oxide.
As alumina is amphoteric in nature, it exhibits a higher solubility at both the extremes of pH range, it is possible to dissolve alumina in low as well as in high pH solutions.
Dissolution of the alumina at high pH is well recognized in Bayer process. Bauxite is digested in very <u>high pH solution (> 13) of alkali</u> like sodium hydroxide at temperature of about 150–250°C and pressure at 20 atm. <u>This is done so that the dissolved alumina is separated from rest of insoluble bauxite minerals. </u>
All those compounds are ionic.
Then they dissociate into ions when they are in water.
I will write the dissociation equations. The charges of the ions is indicated inside parenthesis.
KI -> K (+) + I (-) => two ions
K2SO4 -> 2 k(+) + SO4 (2-) -> three ions
NaCl -> Na(+) + Cl(-) => two ions
KBr -> K(+) + Br(-)
As you se every molecule of the compound K2SO4 dissociates into three ions, while the other compounds dissociate into two ions. Given that the decrase in the freezong point of water is proportional to the number of particles dissolved, the K2SO4 will lower the freezing point the most.
Answer: option B. K2SO4
