To prevent the hydrolysis and to catalyse the reaction.
Explanation:
- Sulphuric acid is the catalyst and also a dehydrating agent in this reaction.
- Sulphuric acid is using in redox reaction because sulphuric acid is providing H+ ions which is necessary for this reaction to occur more quickly, but the sulphate ions from the sulphuric acid barely react during this process. So H2SO4 is adding in this reaction to make it more acidic.
- H2SO4 is preventing hydrolysis by providing excess H+ ions into the reaction. H2SO4 is stable towards the direction of oxidation.
Explanation:
a) Using Beer-Lambert's law :
Formula used :

where,
A = absorbance of solution = 0.945
c = concentration of solution = ?
l = length of the cell = 1.20 cm
= molar absorptivity of this solution =


(
)
14.16 μM is the molarity of the red dye solution at the optimal wavelength 519nm and absorbance value 0.945.
b) 
1 L of solution contains
moles of red dye.
Mass of
moles of red dye:



c) In order to dilute red dye solution by 5 times, we will need to add 1 L of water to solution of given concentration.
Concentration of red dye solution = 
Concentration of red solution after dilution = c'



The final concentration of the diluted solution is 
Well electrons are like electricity well it is partly if it went 3 sub levels the electrons would blow up some electricty<span />
First, you need to calculate the standard cell potential using standard reduction potential from a textbook or online. Since Mg becomes Mg+2, magnesium is being oxidized because it is losing electrons, you need to flip its potential
Fe+2 + 2e- --> Fe potential= -0.44
Mg+2 + 2e- --> Mg potential= -2.37
Cell potential= (-0.44) + (+2.37)= 1.93 V
Now, you need to use Nernst formula to get the answer. I have attached a PDF with the work.