When we do this experiment in the lab, we use a green universal indicator, which changes color according to the acidity/basicity of the solution. Generally, the more acidic solutions tend to be pink, and more basic solutions tend to be blue. What color would you expect the solution to be in the test tube where the hydrogen gas collects

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.