A student titrates 60.0 mL of a nitric acid solution to the equivalence point with 42.0 mL of a 0.30 M sodium hydroxide solution. Phenolphthalein is used as an indicator. When the equivalence point is reach the indicator color change remains and the student stops titrating. After titrating to the equivalence point, what is the concentration of the nitric acid solution?

it is called acid bonding

b is the correct

  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-