Chapter 15 Oxidation + Reduction Flashcards
Potassium Permanganate (molecular formula + type of substance )
KmNO4 , Oxidising Agent
primary standard + 2 properties
can be weighed easily and is so pure that its weight is truly representative of the no. of moles of substance contained. (pure, stable)
Potassium Permanganate (properties 3 )
unstable, decomposes in the presence of light/heat concentration of solutions vary over time
Potassium Permanganate ( equation+ color)
KMnO4 [-] + 8H[+] + 5e[-] {purple} = Mn[+2] + 4H2O {colorless}
Why is Sulphuric acid (H2SO4)added to solutions
is added to prevent hydrolysis and to provide surplus H+ ions in the solution to keep reaction proceeding
why do we read kmno4 from the top of the meniscus instead of the bottom
because of the intense purple color
MNO4- ions reacts with Fe+ ions in what ratio
1:5
Reducing agent (exp 1)
Ammonium iron sulphate
Standard solution
solution of known concentration
why use dilute sulphuric acid when preparing standard sol. from hydrated Ammonium iron sulphate
to prevent air oxidation of the fe [2+] ions in the sol.
why further add dilute sulphuric acid to each 25 cm portion
to prevent MN02 from forming
describe the procedure used that ensured the accuracy of the end point
swirl the flask while adding KMnO4, and add it slowly as end point is approached
No of moles (equation)
mass(g) / moles(avogadro’s constant)
Molarity (equation)
no. of moles /volume of sol.
equation for solving volumetic problems in redox reactions.
Vo * Mo /No = Vr * Mred / Nr {v=vol m=molarity n=no.of moles }
