What is EAN for metal ion in $[\text{Fe(CN)}_6]^{3-}$ ?

Which of the following is a correct increasing order of ligand field strength ?

Identify substrate 'S' in the following reaction.
$\text{S} \xrightarrow{\large{\text{Na / dry ether}}}$ 3, 4 - diethyl - 3, 4 - dimethyl hexane

Select the correct decreasing order of acid strength for the following compounds.
a) Ethanol   b) 2-Methyl propan-2-ol   c) Phenol   d) p - Nitrophenol