The leaving group is that functional group which is ejected with electrons of the o-bond in a reaction. Bette the leaving group, faster is the reaction. The relative leaving abilitiy of the leaving group X in (R-X) is increased by:
i. The polarisability of (R-X) bond ii. The degree of stabilisation through solvation of X.
iii. The strength of (R-X) bond. iv. The stability of `X^(Theta)`.
The leaving group tendency is also called fugacity.
Which statement is correct?

Options

A. `EtO^(Theta)` is a strong base and therefore a good leaving group.
B. The `-NH_2` gorup in `ArNH_2` is converted into a good leaving group by reacting it with `NaNO_2 + HCl " at " 0^@C`.
C. The (OH) group is converted into a good leaving group by reacting alcohols with TsCl (p-toluene sulphonyl chloride).
D. The amine group in `RNH_2` is converted into leaving group by reacting `RNH_2` with `NaNO_2 + HCl " at " 0^@C`.

Answer

C

Explanation

A) `EtO^(Theta)` is a strong base andso poor leaving group.
B) `ArNH_2^1 + NaNO_2 + HCl overset("at"0^11C)to Ar - overset(o+)N -=N - Cl`. The benzene diazonium ion `(Ar overset(Theta)NH_2)` is stabilised by resonance. So, it is a poor leaving group but in `RN_2^(Theta)` it is not stabilised, so it is a good leaving group.
C) `ROH + TsCl to R - O - Ts + HCl. overset(Theta)OTs` is a good leaving group because it is a conjugate base (weak base) of a strong acid (TsOH)
D) `RNH_2 + NaNO_2 + HCl to ROH + N_2 + NaCl`