20
which of these equations is balanced?
a. h2so4 + 2al --> al2(so4)3 + h2.
b. 2kcl + pb(no3) + pbcl2.

a.
b.
a and
b. neither.

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.