If an electron withdrawing group ( $$-I$$ - showing group ) is present, e.g. $$ - C{F_3}$$  has more ( $$-I$$ - effect ) withdrawing power than $$ - CC{l_3},$$  it makes the removal of proton more easy by stabilising the remaining carboxylate ion and thus, makes the acid more acidic.
The order of acidity of given compounds is

$$C{H_2} = CH - C{H_2} - N\mathop = \limits^ \to C:$$
The above structure of allyl isocyanide clearly shows $$5C - H\left( \sigma \right),2C - C\left( \sigma \right),1C - N\left( \sigma \right),1N - C\left( \sigma \right),1C - C\left( \pi \right),2N - C\left( \pi \right)$$              bonds, i.e., $$9\sigma $$ and $$3\pi $$ bonds in all. There are 2 non-bonded electrons on the C-atom (co-ordinate bond between $$N$$ and $$C,$$ the electron pair of $$N$$ is shifted towards $$C$$ ) .

Geometrical isomers The isomers having same molecular formula but differ in the position of atoms or groups in space due to hindered rotation about a double bond.

Hexane $$\left( {{C_6}{H_{14}}} \right)$$  has five chain isomers and these are

3, 3-Dimethylpent-1-ene

Spent-lye and glycerol are separated by distillation under reduced pressure.
Under the reduced pressure the liquid boil at low temperature and the temperature of decomposition will not reach. e.g. glycerol boils at $${290^ \circ }C$$  with decomposition but at reduced pressure it boils at $${180^ \circ }C$$  without decomposition.

Presence of electron releasing groups like $$-R,-OH,$$   etc. increases the electron density at $$o/p$$ - position and thus, makes the benzene ring more reactive ( at $$o/p$$ - positions ) towards an electrophile. On the other hand, electron withdrawing groups like $$ - COOH, - N{O_2},$$    etc. if present, reduces electron density and thus, reduces the activity of benzene nucleus towards an electrophile. Thus, the order of the given compounds towards electrophilic nitration is

Thus, toluene is most reactive towards electrophilic nitration.

Aryl halides do not undergo nucleophilic substitution under ordinary conditions. The low reactivity of halogen atom in aryl halides is due to resonance. However, aryl halides can be made to undergo nucleophilic substitution either under drastic condition ( high temperature, pressure or very strong nucleophiles ) or by activating the nuclear halogen by introducing electron withdrawing group e.g. $$N{O_2}, - CHO,CN$$     etc. in the $$o - $$  and $$p - $$  position to the nuclear halogen. Hence, $$p - $$  nitrochlorobenzene would react most readily with nucleophiles.