Give reason :
(i) `BiH_(3)` is the strongest reducing agent almost all the hydrides of group 15 elements.
(ii) `H_(2)O` is a liquid and `H_(2)S` is a gas.
(iii) Fluorine exhibits only -1 oxidation state whereas other halogens exhibit +1, +3, +5 and +7 oxidation states also.

Consider the situation in figure. The bottom of the pot is reflecting plane mirror , S is small fish is a human eye . Refractive index of water is mu . Fish can see two images of human eye , first due to refractive only and other due to refraction and than reflection . Distance of these images from fish are S_(1) "and" S_(2) respectively . Human eye can also see the two images of fish, first due to refraction only and other due to reflection and then refraction . Distance of these images from human eye are S_(3) "and" S_(4) respectively . Match the quantities of column-I (with their value in column-(II) {:("Column I","Column II"),((A) S_(1),(p)H[1 + (1)/(2mu)]),((B)S_(2),(q) H[mu + (1)/(2)]),((C)S_(3) , (r) H[1 + (3)/(2mu)]) , ((D) S_(4) , (s) H[mu + (3)/(2)]):}