unified

Question 1

equilibrium with cobalt ( p.o.e. with temp.)

Answer 1

[Co(H2O)6]2+ + 4Cl- <—–> [CoCl4]2- + 6H2O
forward is endo
pink<—->blue

Question 2

equation for weak acid

Answer 2

C≈ √(Kₐ × [HA])

Question 3

buffer equation

Answer 3

pH = pKₐ + log([A⁻]/[HA])
and [H⁺]=(Ka x [HA]) / [A-]

Question 4

formula for ionic product of water

Answer 4

Kw=[H⁺][OH⁻]=1x10^-14

Question 5

approximations for weak acids

Answer 5

1- the dissociation of water is negligible
2- the concentration of HA (the acid) is much greater than the [H⁺] at equilibrium.

Question 6

the 2 reaction pathways to form a nitrile

Answer 6

1- haloalkane + NaCN —–> nitrile + NaX
2- carbonyl + HCN ——-> hydroxynitrile + OH⁻
( HCN made in situ with NaCN/H2SO4)

Question 7

hydrogenation/reduction of a nitrile

Answer 7

nitrile + 2H2 ——> amine

Question 8

hydration of a nitrile

Answer 8

nitrile + 2H2O + HCl——-> carboxylic acid + ammonium salt

Question 9

alkylation of benzene

Answer 9

benzene + haloalkane—–> alkyl benzene +HX
needs halogen carrier

Question 10

bond angle and shape of a pyramidal shape

Answer 10

109.5 degrees
1 lone pair of electrons with 3 bonded pairs

Question 11

colour of Cr3+ ions

Answer 11

green solution

Question 12

colour of CrO4- ions

Answer 12

yellow solution

Question 13

colour of Cr2O72-

Answer 13

orange solution

Question 14

colour of MnO4- ions

Answer 14

purple solution