An element used in the production of matches is

Which of the following gases may not be dried with concentrated sulphuric acid?

The Consecutive members of an alkane homologous series differ by

A correct electrochemical series can be obtained from Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that