Why should taste NEVER be used as a test to identify an unknown chemical? A. Many acids are both poisonous and corrosive
B. Taste is often misleading.
C. Many acids and bases are poisonous.
D. Many acids and bases are corrosive.

am i too late?

explanation:

  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-

a electronegativity decreases beacuse the size of nucleus is bigger.

i'm wiling to try and you : )