The displacement of electrons in a multiple bond in the presence of attacking reagent is called

Explanation

a. (I) is terminal alkyne and gives white precipitate of with `Ag(NH_3)_2Cl` or red precipitate of with `[Cu(NH_3)_2]^(o+) OH^(o+)`, whereas (II), an internal alkyne, does not.
b. (III) is a propargylic bromide and gives a pale yellow precipitate of `AgBr` with `(AgNO_1+C_2H_5OH)`, whereas (IV) is a vinylic bromide and does not give any reaction with `AgNO_3`.
c. (VI) is unsaturated compound and gives the test for unsaturation, i.e., decolourisation of pink colour of Baeyer's reagent (cold alk. `KMnO_4`) of discharge of reddish brown colour of `Br_2` solution, whereas (V) is inert.
d. (VII) will react with `H_2+` Lindlar's catalyst or with `H_2+P-2` catalyst `(Ni_2B)` to give (VIII), whereas VIII will not react.
Moreover, quantitative catalytic hydrogenation will also distinguish the two, (VII) will require 2 equivalent of `H_2`, whereas (VIII) with require 1 equivalent of `H_2` per mole of each compound.
e. `(X)` is a symmetrical alkyne and undergoes oxidative ozoolysis to give a single acid (butanoic acid, , whereas (IX) gives two separable acids (propanoic acid) + pentanoic acid, .
f. Quantitative catalytic hydrogenation will distinguish the pair. (XI) will absorb 4 equivalent of `H_2`, whereas (XII) will absorb 2 equivalent of `H_2` per mole of each compound.
Moreover, (XII) will undergo Diels-Alder reaction, whereas (XI) will not.

g. (XIII) is conjugated diene and will undergo Diels-Alder reaction.
h. (XV) has a chiral centre and is resolvable whereas (XVI) is not.