Doping is the process of increasing the conductivities of the intrinsic semiconductors by adding suitable impurity.

In the metallurgy of aluminium, steel cathode and graphite anode are used. The graphite anode is useful for the reduction of Al₂O₃ into Al.

2Al₂O₃ + 3C  --->  4Al + 3CO₂

                          (graphite)

The oxidation state of P in   is +5 while in  is +3. As we know that the stability of the +5 oxidation state is highest on top of the group and decrease down the group and stability of +3 is low on the top of the group and increase down the group.

Therefore    is more likely to exist.

With the increase in alkyl group, the +I effect will increase which will increase the ease of donation of lone pair electron .But in water one other factor is controlling the strength of basicity. Amine will accept a proton and from cation will be stabilised in water by salvation (by hydrogen bonding).better the salvation by hydrogen bonding higher will be the basic strength.

(CH3)₂ NH > CH₃ NH₂ > (CH₃)₃ N > NH₃

Molality of solution = m = 1.00 m

 Boiling points of solution = T_b = 100.18⁰C = 373.18 K

 Boiling point of water (solvent) =  = 100.00° C = 373 K
Elevation in boiling point =   - T_b

 Observed boiling point = 373.18 K - 373 K = 0.18 K

 K_b water = 0.512 K kg mol^{- 1}

 ∴  T _b= K_b x m

 = 0.512 x 1 = 0.512 K

 ∴ Calculated boiling point = 0.512 K