Which of the following options represents the correct
bond order ?

An organic compound 'X' having molecular formula
C₅H_10O yields phenyl hydrazone and gives negative
response to the Iodoform test and Tollen's test. It
produces n-pentane on reduction. 'X' could be :-

Which of the following pairs of ions are isoelectronic
and isostructural ?

The activation energy of a reaction can be
determined from the slope of which of the following
graphs ?

The species Ar, K+ and Ca²⁺ contain the same
number of electrons. In which order do their radii
increase ?